Achieving 1,000,000% Completion in The Binding of Isaac: Afterbirth+ – Steam Solo (2024)

Overview

This is not your ordinary “list all 403 achievements and their descriptions” guide. The achievement descriptions of The Binding of Isaac are sometimes vague as hell so I made an in-depth method for unlocking every single item, character, trinket, floor, etc in The Binding of Isaac: Rebirth, Afterbirth, and Afterbirth+. The game does well with giving an achievement for every in-game unlock so you will also 1,000,000% complete the game by getting every achievement and following this guide. Good luck!Warning: This guide is updated for Afterbirth+ and details listed here may be incorrect if you have an older/newer expansion of the game.

Introduction

Hi, I am a big fan of The Binding of Isaac: Rebirth (I have 452 hours in the game as of writing this) and I tried my best to complete this game to 1,000,000% without the use of any guides or wikis. I actually got pretty far but came to the conclusion that completing this game is too big of a task to do on pure self-discovery alone. Now that I have 1,000,000%, I discovered how useful having a guide is to completing this game and also noticed that most steam guides and wikis are a bit… lacking in terms of offering advice or methods to various unlocks.

In their defense, a good chunk of Isaac’s unlocks and their descriptions are really self-explanatory, but not everything is and I can imagine trying to unlock all 403 achievements (or Secrets as I will refer to them) can be really overwhelming for a new player. So I’m going to go over every single Secret and its unlock method listed in the order that Steam lists them. This guide also serves as an achievement guide as every Secret has and achievement and vice versa.

This guide does SPOIL EVERYTHING so explore at your own risk. I attempt to hide random spoilers in unrelated Secrets, but you should use Ctrl + F (or whatever it is on Mac) to find a specific Secret if that’s what you’re here for. This guide makes liberal use of grouping various Secrets together so if you cannot find a specific item using Ctrl + F; try searching for it’s category (the specific location/boss in question for example).

Words of note before we start though:

1. To address the elephant in the room, this guide is NOT updated for Repentance. Methods in this guide may be outdated or incorrect if the player owns Repentance. The expansion made me wonder if I should even release this guide now. I ultimately decided that I won’t update this guide for Repentance until I’ve truly mastered that expansion so that I can write the best completion methods I can. I will be updating the guide periodically with some more important Repentance stuff, but don’t expect a total overview on this guide for a fair bit of time.
2. Isaac is a fantastic game but even 110%, let alone 1,000,000%, completing this game is not for the faint of heart and requires a large amount of time commitment. Even with the guide, I could still foresee fully completing Isaac taking an inexperienced player anywhere from 150-200 hours of playtime to 1,000,000%. Unless you are dedicated, I would just stick to the various Endings, Completion Marks, and consider Platinum God your completion goal.
3. You should try to play in Hard or Greedier Mode (once you unlock it) pretty much 100% of the time if you’re in hardcore completion mode. There are many, many Secrets tied directly to doing everything in Hard Mode. The difficulty curve that comes with playing only on the harder modes is rough (and optional), but it can save you much pain in the future. It is important to note that Repentance makes Hard Mode even more difficult, so if you have that expansion then think twice.
4. I won’t act like this guide does the best job at explaining every facet of The Binding of Isaac: Rebirth. There are much better places for general information on the game such as
   the wiki[bindingofisaacrebirth.gamepedia.com] or other steam guides I wish I knew about prior to completing this game. My personal favorite being The Bindening™ (link below). As for myself, I am just throwing my own hat in and not attempting to be the “new definitive Isaac guide” or anything like that.
   [link]

Prologue: Keywords

Secret – Another word for achievement. Unlocking literally any achievement in Isaac will put a piece of paper to the screen saying what you unlocked. I assume the game calls these Secrets because said piece of paper refuses to tell you how you unlocked it.

Completion Secret – These have their own section at the ending of the guide because they are Secrets that unlock nothing and merely demonstrate your mastery and/or completion of the game.

Ending – There are 21 Endings in the game, but you’ll get every single one of them in the process of finishing even a single Character’s Completion Marks so it’s not too big of a deal.

Floor – The level you are currently on. There is usually 2 Floor per Chapter until you reach Chapter V, at which then Floor # does not really matter anymore. For example, Chapter III could also be called Floor 5 & 6 while Chapter V can be any variety of Floors depending on Optional Floors you visit inbetween.

Chapter – There are 6 main Chapters in the game which you progressively unlock as I will explain in Part 1.

Secret/Optional Floor – There are two of these in the game and both contain very tough bosses. As a note, there are also two Completion Marks that can be gained in Chapter III and Chapter VI that feel like a new Floor but aren’t.

Alternate Floor – I don’t use this keyword a lot in the guide, but basically Chapters I – IV can gain alternate forms such as Basem*nt becoming either the Cellar or Burning Basem*nt. They do not change Chapter or Floor order in any way and are just a new coat of paint with different enemies and bosses.

Character – It’s you and who you decide to play as when you start a run.

Completion Mark – Each Character has a little paper on their Character selection screens and when you pause. As you beat certain bosses or complete specific tasks, you’ll unlock Secrets which are displayed in the little paper. I will explain how to get each of these in the rest of the guide, but in case you want to know now, the symbols are as such (from top-left to bottom-right). BIG SPOILERS BELOW!

Heart = Mom’s Heart or It Lives!, Cross = Isaac, Star = Boss Rush, Upside-down Cross = Satan, Photo = ???, Inverted Photo = The Lamb, Brimstone = Mega Satan, Cent = Ultra Greed, Tears(?) = Hush, Tearing of the Paper = Delirium. Any of these symbols being in blood means you’ve done it in Hard Mode and this is important because there is a Secret for doing all of a Character’s Completion Marks in Hard Mode.

Hard Mode – Selected when you choose your Character, this mode makes special multicolored versions of enemies and bosses called champions as well as curses much more frequent and generally makes the game trickier.

Greed/Greedier Mode – Selected when you choose your Character and operates completely different from the base game of Isaac. The idea is that you fight waves of enemies and then bosses to earn money. Money is then spent in a constantly restocking super shop. Greedier is the Hard Mode of Greed and must first be unlocked by the Greed Donation Machine.

Boss Room/Treasure Room/Shop – Three rooms that all spawn throughout the game and serve distinct purposes. There are tons of special rooms in The Binding of Isaac, but these are the most important:

• Boss Rooms are where you fight a boss and how you progress onto the next Floor. Bosses are determined by the Floor you are on and, on Floors 6, 8, and onward, become pre-determined bosses that almost never change. At the end of any boss in Chapters I – IV, you receive an item (usually a stat up one).
• Treasure Rooms are rooms that locked on every Floor other than the first one. Treasure rooms only show up for Chapters I – III and grant free items that are usually more powerful than what you get from Shops or Boss Rooms.
• Shops are where you spend coins and are always locked. They have pickups and Shop-specific items for sale. Items in the Shop can have their prices randomly become red, which means they are on a 50% sale. Shops also contain the Donation Machine described below.

Devil Deal/Devil Deal Room – Devil Deal Rooms can be found as early as Floor 2 and normally have a high chance (85% – 100%) to show up after the boss is killed. Chances can also be raised slightly by certain actions. Devil Deal Rooms will stop showing after Chapter IV and on Optional Floors. Devil Deal Chance drops by roughly 40% each under these two conditions. The two conditions are:

1. You take “red heart” damage in the current room you are in. Note that soul hearts and black hearts are not included in this and can be used to shield your Devil Deal chances.
2. You take “red heart” damage at any point on the Floor. This effectively means that taking “red heart” damage your first time in the Boss Room will plummet your Devil Deal chances to almost single digits.

Angel Room – If you fulfill the conditions to get a Devil Deal Room and then ignore trading health within it, you will increase your chance to get an Angel Room to about 50%. Afterwards, when causing a Devil Deal to happen, you will get an Angel Room instead. You can enter a Devil Deal Room and open chests within it, but you cannot take an item through means of giving up health. Angel Rooms give their own special items and they are completely free to boot, but are arguably not as good as Devil Deal items.

Secret Room – There are 1-2 of these rooms on every Floor and are found by bombing walls. Secret Rooms have their own method of being found, but it’s a little complicated and requires good gamesense on how Floors are generated. These rooms can have enemies, items, coins, or literally nothing.

Donations Machine – There are 2 of these in the game, one in normal Shops and another at the end of Greed Mode. Many Secrets are tied to the filling of both of these up to 1,000 coins so that’s why I’m making them a keyword now.

Challenge – While on the main menu, you may notice the Challenges menu. This has 35 challenges, some of which need to be unlocked. I’m making a section at the end for describing how to unlock and beat every Challenge because unlocking a Challenge and the item you unlock beating it both count as Secrets.

Transformation – There are ways to upgrade your Character beyond just items and pickups. The most notable way is a Transformation. Upon picking up a series of (usually 3) items or effects, you gain a permanent upgrade for free. These items or effects typically have a theme (Guppy, Mushroom, Flies, etc) and are needed for some Secrets.

Part 1: Unlocking Floors

The Womb
Chapter 4 – The Womb unlocked.
When you first play The Binding of Isaac: Rebirth you will only need to make it through the first 3 Chapters. The boss of the Depths II will ALWAYS be Mom and killing her gives you your first Ending and unlocks Chapter IV for subsequent runs.

It Lives!
You’re future’s past awaits.
After unlocking The Womb, you’ll be able to make it all the way to Womb II where the boss will (much like Mom) always be Mom’s Heart. Each time you beat it, you’ll get a new Ending and Secret up to 11 times. After the 11th time, Mom’s Heart will permanently transform into It Lives!. Beating it allows you to progress to either of Chapter V Floors. The two Chapter V Floors are The Cathedral (light beam) and Sheol (trapdoor). The transformation to It Lives! does not change any Completion Marks or Secrets related to killing Mom’s Heart.

The Polaroid & The Negative
Unlocked new items.
These 2 items are unlocked by beating the boss for The Cathedral and Sheol 5 times each. When either The Polaroid or Negative are unlocked, they will appear as the boss reward for killing Mom instead of a generic item. You then can choose one and only one. Opening the chest that spawns after completing The Cathedral with The Polaroid in hand will take you to Chapter VI: The Chest. The same thing can be done with The Negative and Sheol’s chest, which will take you to a different Chapter VI: Dark Room. Having the wrong one of these items for their respective chest will end your run right then and there.

Angels
They are waiting.
As soon as you get to either Chapter VI Floors, you may notice a giant, locked golden door that isn’t needed to fight the boss of The Chest or Dark Room. Upon clearing either Chapter VI, you will get the “Angels” Secret, which unlocks 2 hidden boss fights. If you bomb or explode the angel statue in any Angel Room, you will start a fight with either Uriel or Gabriel as a boss. You can fight the angels before getting this Secret via Boss Rush, but they cannot be fought in an Angel Room. Each one will drop a Key Piece upon death in an Angel Room. If you kill both of them, each in a different Angel Room, you will form a complete key that can be used to unlock the golden door in Chapter VI where you then fight the true final boss… of Rebirth that is.

Note: The following entries are considered Secret/Optional Floors or have to do with Greed Mode. Some of the upcoming entries are not achievements or Secrets themselves.

Boss Rush
Not a Secret.
The Boss Rush is an optional fight you can take on for a Completion Mark. You access the Boss Rush by killing Mom in under 20 minutes, at which then a hole will open up in her boss fight arena. Here, you can choose a free item out of a few choices and then will fight a whole series of bosses from Chapters I to IV. This is very challenging and requires a lot of preparation so be wary.

Blue Womb
Unlocked a Hidden Chapter.
After you’ve beaten Mom’s Heart 10 times and beat It Lives! in under 30 minutes, you’ll be able to access a Secret Floor. Much like with Boss Rush, a hole opens in the arena that takes you to a new Floor known as ??? or the Blue Womb. You will get 2 Treasure Rooms, 4 gold chests, and a Shop, and trust me… you’ll need it.

New Area, Delirious, and Lil’ Delirium
Unlocked a new area.
Completing the Blue Womb once will give you a new Ending. After that, clearing it gives a 100% chance to find a Void Portal in a room above the boss arena. Other pre-determined bosses listed above will also have increasing chances to spawn a portal, but no guarantee. Going through the Void Portal will take you to The Void, a massive Floor with many Boss Rooms containing bosses. One of these Boss Rooms, at random, has a chance to be the true endgame boss. Kill this impossible boss fight and you will unlock the Delirious Secret as well as Lil’ Delirium.

Greed Mode
Not a Secret.
Greed Mode is an alternate playstyle to the base game that involves fight waves of enemies and the collection of money for everything. There are 6 Floors of Greed Mode followed by a final Floor called Ultra Greed. Here you fight the unique pre-determined boss called Ultra Greed and gain a Completion Mark for killing him.

Greedier!
New mode unlocked!
Every time you beat Ultra Greed, a Donation Machine called the Greed Donation Machine will spawn and allow you to put any leftover coins you have into it. This machine has a chance to break depending on how many coins you’ve put in with your specific Character. Many Secrets are tied to milestones of the machine, with 500 coins being the way to unlock Greedier Mode. Greedier Mode functions as the Hard Mode of Greed Mode with another unique 2-phase endgame boss called Ultra Greedier. There are unique Completion Marks tied to Greedier mode (bloodied cent); however, you can obtain Greed Mode marks at the same time you get Greedier Mode marks.

Part 2: Characters & Upgrades (1/2)

The D6
Isaac now holds the D6!
Isaac himself does not have to be unlocked, but he does get one upgrade that makes him quite a bit stronger. To get this upgrade, you have to unlock the D6 and then Isaac will always start with it as well as adding the D6 to the item poll. To unlock the D6, kill the boss of Chapter V: The Cathedral as ???, whose unlock method is shown below. The D6 allows Isaac to reroll item pedestals he finds, giving him much more agency over his runs.

Magdalene
Unlocked a new character.
Maggy has a very simple unlock with many strategies to it. Simply do as her unlock method on the character select states and have at least 7 red heart containers. The max red heart containers are 10 so you’ll need over half max health to accomplish this. The best advice I have is to avoid having too many soul hearts and avoid Devil Deal Rooms like the plague; Angel Rooms often give you HP up items anyway.

Maggy Now Holds A Pill!
Unlocked a new starting item.
To get a guaranteed Speed Up pill for Maggy, you need to beat the “Aprils Fool” Challenge from Afterbirth+. This challenge does a lot to screw with player by showing incorrect sprites and maps along with a bunch of other minor things (the wiki has a complete list, far too many to put here). The hardest part of this challenge is that every boss down to The Womb (the end goal) is The Bloat. Do Boss Rush a whole bunch of times to get really good at fighting The Bloat and then this challenge isn’t so bad, just annoying.

Cain
Unlocked a new character.
This Secret requires that you have 55 cents at any time. This is not nearly as hard as it sounds (Cain was the first Character I unlocked besides Isaac). You can just not ever spend money and hope that it’s enough by the end of your run. While doing this, always visit Shops and Secret Rooms as you may fight Greed and gain a lot of money in doing so.

Cain Holds Paperclip
Unlocked a new starting item.
This Secret requires you to donate 68 cents to the Greed Donation Machine in Greed Mode.

Judas
Unlocked a new character.
To unlock Judas, you need to make your way to Chapter V: Sheol (shown in Part 1) and kill the only boss of that Floor.

??? (AKA Blue Baby)
Unlocked a new character.
Unlocking this Character is the very last thing you do before unlocking It Lives! by having you kill Mom’s Heart 10 times, while It Lives! is the 11th time.

Eve
Unlocked a new character.
Much like Cain, Eve’s unlock sounds a lot harder than it actually is. You need to make it through any 2 Floors in a row without picking up a heart of any kind. Having Maggy unlocked really helps with this task since she has a self-heal and the most starting health. You could also wait until a later Floor in your run once you’ve built up a good supply of soul hearts and attempt to just tank it through. Lastly, playing The Lost or Keeper will automatically get you this character unlock as neither can even pick up hearts.

Eve Now Holds Razor Blade
Unlocked a new starting item.
This Secret requires you to donate 439 cents to the Greed Donation Machine in Greed Mode.

Samson
Unlocked a new character.
Now this Character unlock is actually a little bit tricky. You need to complete any 2 Floors in a row without taking damage. Unlike with Eve, you should attempt to do this with only the first 2 Floors and simply reset if you fail. Most Chapter I bosses are pretty easy so your biggest risk is the rooms in-between the Boss Room. Don’t try to explore unneeded rooms, just rush the Treasure Room (optionally) and then Boss Room in that order. Unlocking this Secret using this method will also get you the Basem*nt Boy Completion Secret.

Samson Feels Healthy!
Unlocked a starting item.
To start with the Child’s Heart trinket with Samson, you need to beat the “Ultra Hard” challenge from Afterbirth+. This challenge is extremely difficult and since Samson is already a very strong Character; it’s advised to not attempt this challenge until the end of your completion journey. The challenge makes every enemy and boss a champion, allows no kind of hearts, enables every curse, and has you go to Mega Satan. Other than just general mastery of the game, the only strategy to this to make the best of non-heart healing you get and always wait until low health for things like Rainbow Poop or items like <3 (if you can predict said things showing up). The champions and curses are difficult, but it’s mainly just the lack of hearts that makes this so tough so always be wary of bad damage.

Azazel
Unlocked a new character.
To unlock Azazel, you need to make 3 Devil Deals in one game. When you are unlocking Azazel, you should take at least one item of every Devil Deal you can in order to avoid Angel Rooms and also make sure you have a low amount of red hearts. Low red hearts reduces your chance of losing the Devil Deal while not screwing you for health. If you somehow don’t have Azazel before The Lost, then it’s important to note that The Lost gets Devil Deal items for free.

Lazarus (Unrisen & Risen)
Unlocked a new character.
In order to unlock Lazarus, you need 4 soul hearts at a single time. I do not believe that sin hearts and other temporary health contribute to this but I may be wrong. Some items such as PJs, Dark Bum, and many Angel Room items give you soul hearts or increase your chance of finding them so look for those kinds of items. Otherwise, you can blow up tinted rocks (rocks with Xs on them) and visit Shops in order to find easy soul hearts.

Laz Bleeds More!
Unlocked a new character.
To start with the Anemic item with Unrisen Lazarus, you need to beat the “Backasswards” challenge from Afterbirth+. This challenge is basically a Mega Satan check as it starts you with 10 random items and the Mega Satan fight. After the fight, you go back through the Floors while losing 1 item and heart container each Floor. The latter portion of this challenge is pretty easy, you’ve just gotta be able to beat Mega Satan with a potentially trash set of items. Luckily, this challenge also creates a good opportunity to practice the fight a lot.

Eden
Unlocked a new character.
Eden is your very first unlock for beating Mom’s Heart. This alone is not much of an issue but Eden also requires a currency to play them called Eden Tokens, with one token per play of Eden. You gain a token each time Mom’s Heart/It Lives! is killed and Eden becomes unplayable if you run out of tokens. Eden has no starting items and has completely random stats, trinkets, and items each time you play them.

Part 2: Characters & Upgrade (2/2)

The Lost
Unlocked a new character.
Back in Rebirth, The Lost was a super-secret Character with an insanely complicated unlocking method that required digging through various puzzles the game had. When Afterbirth came out, this method was thankfully simplified to a 2-step process. Step one, unlock the Missing Poster trinket by killing the boss of Chapter VI: Dark Room with Isaac. Step two, find one of those sacrifice rooms (room with one set of spikes alone in it) and kill yourself on it while holding the Missing Poster. You will respawn as The Lost and unlock him.

The D4
Unlocked a new item.
Like with Isaac, to get this upgrade for The Lost you have to unlock the D4 itself and then he will always start with it as well as adding it item poll. Unlocking the D4 is pretty straightforward and just takes some time. You have to find arcades which can be found in Chapter I – IV, require 1 cent to enter, and contain a variety of machines. Blow up 30 machines within the arcade rooms and you will unlock the D4.

Lost Holds Holy Mantle
Unlocked a new starting item.
This Secret requires you to donate 879 cents to the Greed Donation Machine in Greed Mode. This is obviously a lot, but it’s worth it as The Lost dies in one hit and the Holy Mantle can remedy that. It’s advised that you unlock this Secret before you attempt most Completion Marks as The Lost to save your sanity.

Lilith
Unlocked a new character.
Unlocking Lilith is very straightforward and she’s literally a Completion Mark for Azazel, who is arguably the strongest Character in the game. Defeat Ultra Greed as Azazel and you’ll unlock Lilith. She cannot shoot tears herself and relies on her Incubus to do damage.

Keeper
Unlocked a new character.
The Keeper, like The Lost, is a secret Character and literally had a whole ARG tied to him being unlocked within the game (look it up, it’s super cool). Anyway, after that whole ordeal, the Greed Donation Machine was given a cap like the normal Donation Machine at 1,000 cents. At 1,000 cents, the Greed Donation Machine blows up and unlocks the Keeper. Unfortunately, Afterbirth buffed The Lost and so a new challenge Character was needed. The Keeper fills this role by being completely awful in almost every way. The Keeper has 3 upgrades, but they are all tied to his Completion Marks so I won’t be listing them out of redundancy.

Apollyon
Unlocked a new character.
Apollyon is a little tricky to unlock and is surprisingly not tied to the unlocking of Void Portals. All you need to do is kill Mega Satan, but as Part 1 showed, that is not the easiest task and takes a bit of time to get to.

The Forgotten
Unlocked a new character.
Oh boy… this is a bit of a process. The Forgotten is the Afterbirth+ secret Character so it’s a little cryptic. You must have defeated completed Chapter VI: Dark Room at least once before and then you can begin the process.

Step One: Kill the Floor 1 boss in under a minute (indicated by hearing Mom shout) and make your way back to the starting room. In this room, you’ll see a shadow of someone digging something. Bombing the shadow will scare it and drop a broken shovel. Picking it up gives you an active item and a curse that causes Mom stomps to constantly chase you. You can use the shovel to stop the stomps for the current room thankfully. DO NOT drop the shovel in place of another active item as it will disappear once you leave the room.

Step Two: Survive all the way to Floor 6 and beat the Boss Rush (time limit does not apply like normal). You should use the shovel during the Boss Rush obviously, unless you want to get the stomps to possibly kill bosses.

Step Three: After beating the Boss Rush you will get the other half of the shovel and cleanse yourself of the curse. Make your way to Chapter VI: Dark Room and find an empty room with patches of ground that look like dirt. Stand on one of them and use the shovel and you will unlock The Forgotten.

Part 3: Rebirth Secrets (1/3)

The Harbingers
The horsem*n are loose.
This one is simple enough. The Harbingers are 4 horseman boss fights (Famine, Pestilence, War, and Death) that are seen in Chapters I – IV (in that order) and are unlocked when you kill Mom for the first time. They are not the only horsem*n, but are the only Harbingers if that makes sense. Be sure to get good at these fights as they all show up in the Boss Rush and Mega Satan fight. The following Secrets also have to do with the Harbingers.

A Cube of Meat + Related Secrets
Unlocked a new item(s)
The Cube of Meat and Bandage Ball are two items that are ALWAYS found after killing a Harbinger and therefore are unlocked when you unlock “The Harbingers” (see above). The Secret says Cube of Meat, but sometimes the Cube of Meat will not spawn at all and be entirely replaced by the Bandage Ball.

There are two more Secrets related to these items, being Super Meat Boy and A Bandage. Super Meat Boy does not unlock an item while A Bandage does. Both of these require getting 4 of their respective items. There are many ways to do this such as using the Potato Peeler or using Lilith and her Box of Friends. The simplest way is to fight all the Harbingers as proper bosses (Gotta Meat Em All!); which luckily there’s an easy way to do so right below this!

The Book of Revelations
Unlocked a new item.
This item grants a soul heart on use, but also guarantees your next will be one of the 4 Harbingers if the boss isn’t already pre-determined. However, to unlock it you must kill one of the Harbingers. You will probably wind up doing this anyway, but I recommend trying to kill Famine or War first as they are very easy fights. Death is the only Harbinger you really need to worry about.

Mom’s Heart Secrets
A whole bunch of ’em.
In Parts 1-2 I already showed how you can unlock It Lives!, Eden, and ??? with Mom’s Heart. Out of the 11 times you have to kill Mom’s Heart, this makes up the 1st, 10th, and 11th times. Defeating it for the 2nd, 3rd, 4th, 6th, 7th, 8th, and 9th time all gives you specific Endings & Secrets. These Secrets are as follows: Rubber Cement, A Noose, Wire Coat Hanger, Ipecac, Experimental Treatment, A Quarter, and A Fetus in a Jar.

Mom’s Heart is a tricky fight with 1 heart damage, enemy summons, and tricky bullet patterns. Be sure to kill enemies first as it will make the heart invulnerable. Any items that slow bullets or make you invulnerable can save you in the fight. You can also use the bible for a one-hit kill on Mom’s Heart, much like with Mom herself (see below in the “A Halo” Secret).

Boss Rush Secrets
A whole bunch of ’em.
In Part 1 I explained the Boss Rush. For a reminder, beat Mom in under 20 minutes. You can press TAB while in Isaac to toggle a timer if you’re having trouble keeping track. Every Character in the game must make it to the Boss Rush and complete it for a Completion Mark.

Do not let the early placement of the Boss Rush fool you, many of the endgame boss fight Secrets are easier to complete than the Boss Rush depending on the Character (Ex: I beat both Chapter VI bosses with The Lost wayyyyyy before the Boss Rush). This is because the Boss Rush is long, you don’t have a lot of time to get really strong, and there isn’t a real strategy outside of just getting good at almost every Chapter I – IV boss fight. Typically you should only try the Boss Rush if you’ve got a run that prioritizes high damage per second or if you have buff items such as the Strength or Empress tarot cards. Active items are very helpful in the Boss Rush as bosses spawn in sets of two and give you two charges each time this happens; allowing for some real nonsense with items like Box of Friends.

Mr. Mega & A Small Rock
Unlocked new items.
I’ve already sort of talked about tinted rocks in the Lazarus Character Secret, but now is the time to go in-depth. In Chapters I – III, there is a small chance that a rock (no urns, mushrooms, skulls, etc) will be slightly miscolored with an “X” on it. The further you go, the harder it is to spot them but they are there. Blowing up tinted rocks typically gives you either keys or soul hearts. After blowing up 10 you’ll unlock Mr. Mega (often found in Treasure Rooms). Blow up 100 tinted rocks you’ll be able to find A Small Rock in tinted rocks, which is straight damage up item for free.

Monstro’s Tooth
Unlocked a new item.
Possibly the easiest Secret in the game, you just have to make it through Chapter I and enter Caves I. That’s literally it.

Lil’ Chubby
Unlocked a new item.
Much like with Monstro’s Tooth, you just have to clear Chapter II and enter Depths I. This is, of course, a little bit harder but the Caves are just as much of learning process as the Basem*nt.

Loki’s Horns
Unlocked a new item.
You may be familiar with the boss called Loki in Chapter 3. Well, there is a rare chance to get the posthumous version of him (much like other bosses) called Lokii in Chapter 4. Killing Lokii will unlock this item. The boss can effectively only show up on Floor 7 and basically acts as fighting two Loki’s at the same time.

Reference Bosses
New bosses everywhere!
There are 4 alt versions of normal bosses that you can unlock for Chapters I – IV. The overlying theme is that these bosses are references to previous games of The Binding of Isaac’s creator, Edmund McMillen. Upon killing any of these bosses, you get a Secret in the form of a guaranteed drop the first time they die. These Secrets are as follows:

• Something From The Future (Steven as an alt for Gemini) – Unlocked by beating Chapter I 40 times. Unlocks Little Steven once killed.
• Something Cute (C.H.A.D. as an alt for Chub) – Unlocked by beating Chapter II 30 times. Unlocks Little C.H.A.D. once killed.
• Something Sticky (Gish as an alt for Monstro II) – Unlocked by beating Chapter III 20 times. Unlocks Little Gish once killed.
• Something Sticky (Triachnid as an alt for Daddy Long Legs) – Unlocked by completing Chapter V: The Cathedral 10 times. Unlocks nothing once killed : (

Cathedral Secrets
A whole bunch of ’em.
As told in Part 1, you can reach two different Chapter V’s after unlocking It Lives! One of such is The Cathedral, where you fight Isaac as the only boss. Killing Isaac as each of the characters will unlock a item for a Completion Mark.

Isaac is a weird fight because it gets easier the longer it goes. Isaac has three phases, he starts on the floor crying and with fire fast moving tears along with summoning enemies. Soon he will stand up and unleash occasional holy light along with constant streams of very difficult tear patterns. If you survive that, then Isaac will grow wings and teleport into the sky. Once he does that, holy light will begin fill the room. Move to the corners of the room opposite to where the holy light starts or you WILL be hit. Once that’s over, he will teleport back down to do a close range tear attack or two before repeating the process. This last phase is more annoying than anything and it’s mostly the 2nd phase you have to think fast for.

Part 3: Rebirth Secrets (2/3)

The Book of Sin
Unlocked a new item.
Throughout the game, you can run into these mini-bosses named after the 7 Deadly Sins. They can be found in random rooms as a separate encounter, in Greed Mode, in the Mega Satan fight, and Greed specifically can be found by hording too much money in Shops. Each sin has a super variant found randomly (Greed and Pride even have Ultra variants), but I believe you need to only kill the base versions for this Secret. The sins are simple fights compared to bosses with limited movesets and low HP so this Secret is not too difficult.

A Gamekid
Unlocked a new item.
I talked about Arcades in “The D4” section of Part 2. They are special rooms that cost a coin to enter and host various machines. Enter 10 of these and unlock the Gamekid.

A Halo
Unlocked a new item.
In reference to the Epilogue Ending, where Isaac’s Mom dies to a Bible, using The Bible active item will instantly kill Mom, Mom’s Heart, and It Lives! when used in the room. Doing this once to any of them will unlock the Halo item.

The Scissors
Unlocked a new item.
The actual easiest Secret to unlock. Simply die 100 times. You probably already have this one huh?

The Parasite
Unlocked a new item.
To unlock this Secret, you must own 2 of the following items in any run: Bob’s Rotten Head, Dead Cat, Cricket’s Head, Tammy’s Head. Bob’s head is found in treasure rooms and sometimes for killing Sloth. Dead Cat is found in red chests and in Devil Deals. The last two are found in Treasure Rooms and rarely in gold chests.

Everything Is Terrible!!!
The game just got harder!
Those with keen eyes may have noticed I ignored the 5th kill of Mom’s Heart earlier. Well, doing so permanently makes the game harder is a lot of subtle ways. The most notable change is that champion enemies and curses (normally found in Hard Mode) are also a fair bit more common in normal mode and are even more frequent in Hard Mode.

Mom’s Contact
Unlocked a new item.
This requires obtaining the Yes Mother? Transformation, which creates a knife behind you that damages enemies. Items in this Transformation are basically any items that starts with “Mom’s”. These items are typically Shop items or Boss Room items. You can also sometimes get a Mom item by blowing up the vanity mirrors that sometimes appear at the start of a room.

The Necronomicon
Unlocked a new item.
To unlock this Secret, you must use the Death tarot card 4 times. All tarot cards are found in chests, Shops, as room drops, and generated by some items and consumables. Death is not anymore or less common than the other tarot cards so getting an item like Deck of Cards can be very helpful for this Secret. Blank Card can allow you to reuse a Death card multiple times so that’s something to keep in mind.

Sheol Secrets
A whole bunch of ’em.
As told in Part 1, you can reach two different Chapter V’s after unlocking It Lives! Earlier, I went over The Cathedral and it’s items. The other chapter is Sheol, where you fight Satan as it’s only boss. Every character must kill Satan for a Completion Mark. Satan is a 3-phase fight that goes as such:

1. The Fallen along with two explosive leeches. If you can beat The Fallen or Krampus, you can beat this phase.
2. Satan themselves with stand up and begin to fire upon you. Standing to either side will cause them to fire a series of fast bullet patterns that can be tricky to dodge. Going into the middle will have Satan fire a large brimstone laser like The Dark One. The strategy is to rotate between sides to force Satan to constantly change their attacks to hit you.
3. Satan will stand up and begin to stomp on you with goat legs just like Mom’s foot. There are two and sometimes an explosive leech will spawn. Always keep moving to avoid the legs and only stop if both are on the ground. Satan can step on the leeches for massive damage so exploit this the best you can.

Dark Room Secrets
A whole bunch of ’em.
As said in Part 1, you can reach the “final” Chapter known as Chapter VI. Just like Chapter V, there are two different Chapter VI’s, but there is no way to accidentally enter the other one or end your run as long as you grab The Polaroid or The Negative for The Chest and Dark Room respectively. The only boss of Chapter VI: Dark Room is The Lamb. Every character must kill The Lamb for a Completion Mark.

The Lamb is a tricky fight due to its wide variety of attacks. It will slowly float towards you and unleash a variety of bullet attacks. All the bullets appear purple despite often not being homing, but still do not get close since some bullet attacks explode at random. After enough damage, The Lamb’s head will separate from it’s body and become two different things to kill. The body occasionally fires explosive shots and spawns flies while the head is the big issue. The head will spit a flurry of difficult bullet, fire, and brimstone laser attacks that can overwhelm you. The Lamb doesn’t have too much HP so this fight is mostly of endurance and quick thinking.

The Chest Secrets
A whole bunch of ’em.
As said in Part 1, you can reach the “final” Chapter known as Chapter VI. Just like Chapter V, there are two different Chapter VI’s, but there is no way to accidentally enter the other one or end your run as long as you grab The Polaroid or The Negative for The Chest and Dark Room respectively. The only boss of Chapter VI: The Chest is ???. Every character must kill ??? for a Completion Mark.

??? is similar to Isaac’s fight but different in a few ways. Most notably, ??? loses the holy light attacks and instead spawns a large quantity of flies and much more difficult homing bullet attacks. You do not need to run around the room like in Isaac’s fight, but never get too close to ??? and make sure any flies it spawns are dealt with swiftly.

Dad’s Key
Unlocked a new item.
In Part 1, I detailed how the Angel fights work and how to access Mega Satan. If you ever collect both Key Pieces, you will unlock this item. This item is the only other way to open the Mega Satan door in case you were curious.

Donation Machine Secrets
A whole bunch of ’em.
The Donation Machine is a machine found sometimes in Shops that allows you to deposit coins into a counter that saves between runs. When depositing coins, both your Angel Room chance and luck can go up the more coins you put in. There is a small chance that putting in a coin will break the machine for the rest of the run, meaning that you will likely have to fill the Donation Machine over many, many runs. Avoid exploding the Donation Machine as it will remove coins from it. There are Secrets for reaching various milestone in the Donation Machine as follows:

• Blue Map – 10 coins will unlock this item.
• Store Upgrade Lv. 1 – 20 coins will increase the amount of items that is available in Shops.
• There’s Options – 50 coins will unlock this item.
• Store Upgrade Lv. 2 – 100 coins will increase the amount of items that is available in Shops.
• Black Candle – 150 coins will unlock this item.
• Store Upgrade Lv. 3 – 200 coins will increase the amount of items that is available in Shops.
• Red Candle – 400 coins will unlock this item.
• Store Upgrade Lv. 4 – 600 coins will increase the amount of items that is available in Shops.
• Blue Candle – 900 coins will unlock this item.
• Stop Watch – 999 coins will unlock this item.

Lucky Toe
Unlocked a new item.
Fun Fact: You can blow up the Shopkeepers seen in Shops and Secret Rooms. Doing so can spawn spiders, coins, or nothing as well as raising your Devil Deal chance. Blowing up 20 Shopkeepers will unlock this Secret.

Part 3: Rebirth Secrets (3/3)

Counterfeit Coin
Unlocked a new item.
In Arcades, Greed Mode, and sometimes at random you can find a Shell Game that looks like a beggar above 3 skulls. Here you can play a nearly impossible version of the Shell Game in exchange for a coin. Play this game 100 times to unlock this Secret.

Guppy’s Hairball
Unlocked a new item.
To unlock this, you must gain the Guppy Transformation. This is done by picking up 3 “Guppy’s” items (Dead Cat is also included). Guppy items are very regularly found in red chests and Devil Deals, but can be spotted elsewhere occasionally. It’s generally good to get the Guppy Transformation when you can as it allows you to spawn friendly flies for every single time you deal damage (this is VERY good).

A Forgotten Horseman
Unlocked a new boss!
This is one of the two bosses that makes me specify Harbinger from horseman. Conquest is a horseman that can be found in Chapter IV, but must be unlocked by taking 10 Angel Room items. Conquest is actually easier than Death, only being trouble through homing shots and holy beams, and only drops White Pony upon being killed.

Lucky Rock
Destroy 100 rocks.
This is one of the few items whose subtext literally just tells you what to do. I’m not even needed for this one!

Rebirth Alternate Floors
It’s about damn time I used this keyword!
The Binding of Isaac: Rebirth has an unlockable Alternate Floor for Chapters I – III. Each of them require you to beat all of the bosses on their respective Floors, but not necessarily within their respective floors. This means that both the Boss Rush and Greed Mode are very helpful for accomplishing these.

Chapter I receives The Cellar, Chapter II has The Catacombs, and Chapter III gets Necropolis. Each of these Alternate Floors has new enemies, room layouts, and bosses. The Cellar specifically does not require defeating Steven, but does require defeating the baby of Gemini first.

Krampus & Head of Krampus
Unlocked a new mini-boss and item.
Upon taking 20 Devil Deal items, you can unlock a mini-boss that will show up in Devil Rooms like Greed in Shops. The fight works a lot like The Fallen, but Krampus does not split in half and can rotate his brimstone lasers as well as shoot them diagonally. Once you kill Krampus, you unlock Head of Krampus and can either get that or the Lump of Coal as a boss reward.

Butter Bean
Unlocked a new item.
To unlock this, destroy 100 poop. Poop is very common in Chapter 1, spawned a lot by Larry Jr. & Dingle, and can be spawned infinitely by ???.

Little Baggy
Unlocked a new item.
To unlock the Little Baggy, you must get pretty close to the Spun Transformation. This Transformation requires you to have 3 needles based items. Little Baggy only requires 2, but limits it to SOME needle items found in Rebirth including: Roid Rage, The Virus, Growth Hormones, Speed Ball, and Experimental Treatment.

Blood Bag
Unlocked a new item.
Blood Donation Machines are machines that deal a half heart of damage (full heart in later Chapters as per usual) and will spit out a varying amount of money until it explodes from overuse. These machines prioritize red health even when you have soul hearts so be careful. Using this machine 30 times will unlock the Blood Bag, an HP up item than can be found in overused Blood Donation Machines. Making yourself invulnerable allows for free uses of this machine.

Mom’s Heart Hard Mode Secrets
Unlocked… some babies?
This is part 1/2 where Hard Mode matters for Completion Marks. Killing Mom’s Heart or It Lives! with any Character on Hard Mode grants a baby for the specific Character. These babies can be used in the little known co-op mode of The Binding of Isaac which is activated by a second controller input. For most, these babies are useless and server just as Secret fodder. Also Apollyon, for whatever reason, unlocks the Smelter item instead of a baby for this Completion Mark.

Lord of the Flies
You became the Lord of the Flies.
Beelzebub is a Transformation you obtain by collecting 3 of the many fly items that are found mostly in Treasure Rooms but not always. This Transformation grants flight and turns all enemy flies into friendly flies. This Secret also unlocks the Angry Fly Secret seen in Afterbirth+.

Part 4: Afterbirth Secrets (1/2)

Blue Womb Secrets
A whole bunch of ’em.
The Blue Womb is an Optional Floor after Chapter IV that I detail the unlocking of in Part 1. Upon entering this floor, you start in a prep room with some gold chests, two Treasure Rooms (2 items to choose between in each), and a Shop. You’ll need these because at the North of the prep room is a large gate that opens when you get close. Enter it and you will face the super hard challenge boss called Hush. Every Character must kill Hush for a Completion Mark.

Hush’s fight is very hard to simply since Hush has a ridiculous health pool and the fight can easily go on for over 5 minutes. The fight starts with fighting a weakened version of ??? that is dealt with pretty quickly if you have solid damage. See The Chest Secrets for tips on ???. After that, Hush will rise from the floor and you’ll notice two things. One, Hush is massive and is almost impossible to miss. Two, Hush is the resident “bullet hell” fight and expects you to maintain damage while bullets fill the screen.

Hush will swap to a variety of different bullet hell attacks as the fight progresses. Sometime it will even go underground and summon enemies, Hush itself being invulnerable during this time. Hush’s most notorious attack is the Continuum shots. Hush will fire tears off-screen, seemingly missing you completely. These tears will come back around from the opposite side of the screen in fast but predicable patters. My strategy is to stand still where the bullets are not flowing through and move very deliberately to another said location if Hush launches another attack.

Hush is one of the only three major bosses to have what is called a “DPS Cap”. This makes it so you can only deal a certain amount of damage to Hush in a short period of time. This means you cannot one-shot your way through Hush and must learn its attacks in order to succeed. My tips are to only attempt Hush on high HP and to bring any bullet stopping items you have such as Infamy, Stopwatch, or the I’m Drowsy Pill. Neither of these trivialize the fight, but will raise your odds significantly.

Ultra Greed Secrets
A whole bunch of ’em.
In Greed Mode, there are three sets of unlocks that can be obtained. One for beating Greed Mode’s final boss: Ultra Greed. The other two I will cover later down the guide. Ultra Greed is on his own Floor after the Shop Floor and is preceded by a mini-boss room. Every Character must kill Ultra Greed for a Completion Mark.

Much like Hush’s fight discussed above, Ultra Greed’s fight is difficult to explain and also has that pesky “DPS Cap”. Ultra Greed will patrol around his arena, spinning and spitting a variety of coin tears. Sometimes he will stomp on the ground to summon keeper heads and some other enemies occasionally. Ultra Greed makes you drop coins when hit, like the other Greeds, and heals from any coins in picks up so be sure to pick up any lose change.

Ultra Greed’s main attack outside of spitting coins and summoning enemies is the slot machine. Occasionally, Ultra Greed will stop and spin his coin eyes. Depending on what they show up as, it will do one of 4 things:

1. Both Eyes Are Bombs – Ultra Greed will fill the room with destroyable bomb coins that will blow up after a few seconds. Ultra Greed blocks during this, receiving extremely reduced damage.
2. Both Eyes Are Hearts – Ultra Greed will fill the room with with destroyable heart coins that will heal Ultra Greed after a few seconds. Ultra Greed acts as normal while this happens.
3. Both Eyes Are Keys – Ultra Greed will fill the room with destroyable key coins that will turn into golden keys. These will unlock the various golden doors around the arena, each door unleashing a swarm of low health Greed Gapers. Ultra Greed blocks during this like with the bomb coins.
4. Eyes Are Different Things – Ultra Greed will drop a few spinning coins and the act as normal. These coins are destroyable, last for a long time, and deal contact damage.

Ultra Greed will become more red and angry as he takes damage. The angrier he is, the most coins and enemies he will spawn and the faster he becomes. Ultra Greed tests your ability to crowd control due to the large amount of stuff he spawns. Not destroying his summons or coin drops can make the fight very difficult for you. Also, generally avoid standing near Ultra Greed as he may walk into you on accident.

Mega Satan Secrets & Mega
More… babies?!
In Part 1, I went over how to get the Key Pieces needed to unlock to door to Mega Satan in Chapter VI. Once going in, you will get to a platform with a pentagram. Standing on this will begin the Mega Satan Fight. Every Character must kill Mega Satan for a Completion Mark. These Secrets, like with Mom’s Heart on Hard Mode, unlock babies for the unseen co-op mode of The Binding of Isaac. Also, if you beat Mega Satan with every Character then you will unlock the MEGA Secret and item.

Mega Satan is a marathon of a fight, requiring you to take on difficult attacks and many other bosses. Mega Satan does not have a health bar and you just need to wail on him. During this, Mega Satan will use their hands and face to perform many shockwave and bullet attacks. Mega Satan may also send in sins to fight you if you’re taking too long to reach his phases. Speaking of, Mega Satan has 4 phases that start after you lower this initial part enough:

1. Mega Satan will stop fighting and summon in Famine and Pestilence. Beat these and you will then fight War and Death. After all 4 Harbingers are beaten, Mega Satan will resume fighting. Conquest and the Headless Horseman are not fought, which is why I’ve never referred to them as Harbingers.
2. Mega Satan will, again, stop fighting and summon Super Envy. Beat it and you will then fight Super Wrath and Super Lust. Beat them and finally you’ll fight Super Greed, Pride, Gluttony, and Sloth. After all super sins are dead, Mega Satan will resume fighting.
3. Mega Satan will… once again… stop fighting and summon a fallen version of Uriel. This fight is identical to Uriel, just miscolored. Kill Uriel and you’ll then fight fallen Gabriel. Kill both angels and Mega Satan will resume fighting.
4. After enough damage, Mega Satan will sink down, seemingly killed. They will then rise as a skeletal version of themselves and unleash a difficult set of bullet and fire attacks akin to The Lamb. This phase does not have much health, and beating it will kill Mega Satan for real this time.

First and foremost, Mega Satan’s hands can be killed, but they will come back after some time. A lot of pre-skeletal Mega Satan’s hardest attacks are because of his hands. Listen for a deep growl because that means they are going to unleash a huge brimstone laser down the middle of the scream. The bosses Mega Satan summons aren’t the hardest, but not being decent at fighting them will make this fight very hard. Try the Backasswards Challenge if you want easy access to practice this fight. Once you kill Mega Satan, you will get an Ending or possible a Void Portal.

Part 4: Afterbirth Secrets (2/2)

Greed Donation Machine Secrets
A whole bunch of ’em.
After beating Greed or Greedier Mode and their respective bosses, a Donation Machine will fall from the ceiling titled “Greed”. You put leftover coins from your run in here with a chance for the machine to break. Like the Donation Machine, different milestones will unlock various items. I’ve already shown some of these Secrets during Part 2, so I will be skipping those ones:

• Lucky Pennies – 1 coin will unlock these items.
• Special Hanging Shopkeepers – 10 coins will unlock this object.
• Wooden Nickle – 30 coins will unlock this item.
• Everything Is Terrible 2!!! – 111 coins will unlock this Secret.
• Special Shopkeepers – 234 coins will unlock this object.
• Greedier! – 500 coins will unlock this Secret.
• Store Key – 666 coins will unlock this item.
• Generosity – 999 coins will unlock this Secret.

Hard Mode Secrets
Even more babies?!?
This is where me telling you to play on Hard Mode at all times comes into play. Afterbirth adds a fun little mechanic where beating all, and yes I mean Afterbirth+ too, Completion Marks on Hard Mode gives its own unique set of Secrets in the form of more co-op mode babies. As someone who did not play on Hard Mode for most of the game, going back and getting all Completion Marks effectively two times is brutal and I would avoid it at all costs. Also, getting The Lost’s version of this Secret unlocks Godhead as an item instead of a baby for some reason.

Part 5: Afterbirth+ Secrets

Void Secrets
A whole bunch of ’em.
The last step along the unlocking of Floors in the normal gamemodes is the “New Area” Secret. I went over the steps of all that and how Void Portals work in Part 1. Upon entering the Void, you will explore a massive floor consisting of room layouts from all previous Chapters. There are many Boss Rooms, all with bosses from previous Chapters and Boss Room rewards for killing them. One Boss Room will randomly host Delirium, the true final boss of the game. Beat it and you get an Ending; all characters must beat Delirium for a Completion Mark (in the shape of the page being torn/bloodied).

Delirium is a nightmare fight that has been criticized for being too random to be considered fair. Delirium will perpetually fire a large amount of slow moving bullets no matter where it teleports to. Sometimes these bullets are explosive or faster, but not commonly. Delirium will also randomly transform into any boss you’ve killed on your run thus far. You do not need to kill the boss as Delirium’s HP is shared, but it will be able to use any of that boss’ attacks. There are very few things that Delirium cannot turn into such as the 2nd phase of Hush. As Delirium takes damage, it will begin to transform and teleport faster to the point where it is difficult to keep track of it. Enemies summoned by Delirium’s forms will remain regardless of what form Delirium takes.

There’s not really a lot to say about strategies in regards to Delirium because of how wild the fight is. Delirium is the 3rd major boss to have that “DPS Cap” mentioned in Hush’s fight. It is also immune to most insta-kill attacks such as the Chaos Card. Your best chance with Delirium is to takes items that make you largely invulnerable and that slow bullets… just like with Hush. The issue is that Delirium’s forms can cause hits that feels almost unavoidable such as a boss off-screen using Brimstone. Don’t beat yourself up if your run ends at Delirium, this fight is just a bit ♥♥♥♥♥♥♥♥.

Ultra Greedier Secrets
A whole bunch of ’em.
Greedier Mode is unlocked within Greed Mode using the Greed Donation Machine. This mode is effectively the Hard Mode of Greed Mode, having the traditional Hard Mode changes along with less money per wave and more waves. Get to the end and you will fight Ultra Greedier, a similar but ultimately very different boss to Ultra Greed. All Characters must kill Ultra Greedier for a Secret. Kill Ultra Greedier will also count as a kill on Ultra Greed for the purposes of Completion Marks.

Ultra Greedier starts out like Ultra Greed, but his rage mechanic grows faster and I believe Ultra Greedier’s 1st phase has more health. Once the phase is over, the golden statue of Ultra Greedier will come to life and begin to attack. Ultra Greedier summons bomb coins, causes shockwaves and explosions with his fists/jumps, shoots explosive coins with his mouth, and unleashes gold brimstone lasers from the various boss doors.

Generally you want to keep a distance from the Ultra Greedier and especially keep to corners to avoid the golden lasers. Any items that negate full heart damage or explosion damage are godsends in this fight and should be prioritized in shops. Ultra Greedier does not have very much health so bursting down this boss in short stretches of making yourself vulnerable is the best way I’ve found to go about it.

More to come soon…

Part 6: Challenge Secrets

Part 7: Completion Secrets

Perfect Chapter Secrets
A whole bunch of ’em.
Basem*nt Boy, Spelunker Boy, Dark Boy, Mama’s Boy, and Dead Boy are Secrets gained for clearing Chapters I, II, III, IV, and VI without taking a single hit. They don’t actually unlock or change anything so that’s why I’m including them here. I do not know why Chapter V does not have a Secret, but I’m not going to argue with it. Just as a note, damage of any kind counts against this so don’t focus soul hearts like you would for Devil Deals. The best way to get these Secrets is to just play The Lost, or generally have damage prevention items like the Holy Mantle as you basically get free hits. Avoid Optional Floors and fights like the Boss Rush as they only serve to make this more difficult.

Golden God!
You are the best!
This is your first proper step in completion and requires completing both Chapter VI’s.

!Platinum God!
OMG!
This Secret is unlocked when you get all 21 Endings the game has (most of them being the Mom’s Heart ones) and all Rebirth Secrets EXCEPT for The Lost and his Completion Marks. Secrets and Completions Marks related to DLC areas or Characters (Lilith, Keeper, Apollyon, and The Forgotten) are not needed.

The Real Platinum God
111% now stop playing!
Considered the full completion of Rebirth. This Secret is the same except it also includes unlocking The Lost and his non-DLC Completion Marks. This is harder than it sounds.

1001%
Nerd x 1000000
This Secret requires the unlocking of Real Platinum God as well as all Afterbirth Secrets and Completions Marks. Yes, this includes The Keeper.

1000000%
Just Stop!
The endgame goal here. Unlock 1001% and THEN unlock every Secret from Afterbirth+ and completely fill out the Bestiary (found in the Stats menu and most likely done long before you get here).

The Final Challenge…

“Wait what? How can there be more?!? I already 1 million percent completed the game for Isaac’s sake!” I can hear you saying. Well, there’s even more and it’s not tied to a Secret. If you’ve already unlocked 1,000,000% prior to reading this, you already know what I mean by the final challenge.

After many events such as Completion Secrets or beating certain bosses, you’ll see that your save file icon changes from when you start up the game changes. Upon getting 1,000,000%, the game ushers its final challenge with your save slot icon and the simple phrase of “2 Save Files To Go!”.

Yes, a challenge for the truly brave and/or stupid, 1,000,000% The Binding of Isaac: Rebirth 2 more times for a total of 3,000,000% completion.

Now I love this game, but I can not stress enough how you SHOULD NOT DO THIS. I can’t even begin to imagine the level of burnout you could suffer from this game by doing everything 2 more times. I know I will not be attempting this challenge; however, if you choose not to heed my advice then I’d love to know how the process for you is so feel free to comment on your progress. Again, there is no achievement tied to this challenge so I won’t go into detail about any of it but it feels right to warn people against this option anyway.

Ending Thoughts & Update Log

Thank you for reading (or skimming) through this guide all the way to the end! I swear it’s not intentional, but I keep topping myself for the level of work that goes into the guides I make so the fact that people actually read them means a lot to me!

That doesn’t mean I won’t be updating this guide though. If you notice any grammatical or factual errors in my guide or have your own completion methods, let me know in the comments or elsewhere. I want this guide to be the best it can be so helping me out is greatly appreciated. I will keep an update log below this so you can know what has been changed prior to this guide’s release.

Update Log:

4/6/2021 – Rebirth, Afterbirth, and some of Afterbirth+ sections done. Guide is officially released!