To do: The USA Wii U version has an Afterbirth executable, despite the fact that Afterbirth wasn't released for the Wii U version. It can be made to work using PC assets.

This game is still under active development. Be aware that any unused content you find may become used or removed in the future. Please only add things to the article that are unlikely to ever be used, or went unused for some time. If they do get used, please remove them from the page and specify in the edit summary!

A remake of The Binding of Isaac, doubling the amount of content, introducing console players to its special brand of dead baby jokes, bringing in an all-new soundtrack courtesy of Ridiculon, and freeing it from the painful bonds of ActionScript 2.0.

Sub-Pages

Afterbirth The first DLC for Rebirth; they didn't keep the old man

Afterbirth+ The second DLC, with "monthly" Booster Packs

Developer Messages

Hidden message

The following message can be found in resources/packed/readme.txt, warning hackers not to spoil the game for others.

You might wonder how you can open those .a files. Currently there are no

tools available, and there is a reason to it.



Binding of Isaac: Rebirth has a lot of content that is unlocked as you

progress. It also contains some secrets.

We felt that having a folder with all the spritesheets, cutscene videos,

data files and whatnot would be too tempting for people to ignore.

Finding out things while playing the game, either alone, with friends,

or as part of an online community can be a very rewarding experience. We

don't want to take that away from you.



In case you like reverse engineering and absolutely want to take this

beautiful game apart, we would ask you a few things.

 - Don't release any secrets you find to the internet.

 - Don't publish information on how to open the game's data files.

 - Don't give away the unpacked resources.

The least you can do is wait until the game has been released for a

couple of months, so you don't accidentally spoil it for others.



If you have any questions, write to isaac@nicalis.com.

Ending descriptions

To do: Check if removing the comment will affect the ending IN-GAME. This was only tested in the menus. Also check if the Afterbirth clips have anything on the .xml, I don't own the DLC to check this.

The cutscenes.xml is a file that stores each of the game's endings, as well credits and the epilogue sequence. It's possible to select any ending (after unlocked) on the options menu, however, none of them have any descriptions about it.

On the .xml file, a commented string "<temporary text=" exists. Removing the comments, and opening any of the endings via the Menu will show a "placeholder" screen with the ending's name (the Ending Name is found above the temporary text as "name="""> along with the description and what it unlocks (next to the ending's name, with parenthesis), the gray background slowly fades to dark gray to light gray. The following pictures are how the game shows those placeholder screens (in order of the Endings tab found in-game). The Epilogue and Endings 10 and 11 have no text associated with, so the video-clips plays automatically. Note that playing the Ending 10 and 11 causes the Credits to pop-up again, however, the temporary message for the Credits won't show up when loading these two endings.

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Test Rooms

(Images are taken from a room editor)

Room file: 00.special rooms.stb
Room Type: 1
Variant: 0

The very first room in the game (by ID, anyway), this room contains 12 random items and 8 random trinkets.

Room file: 00.special rooms.stb
Room Type: 1
Variant: 1

The second room by ID, this tests the suction of the Gaping Maw entities.

Unused Graphics

Half Hearts

Image file: gfxitemspick upspickup_001_heart.png

Half-heart versions of the Soul Heart and Black Heart pickups. These aren't seen anywhere in the game; indeed, they're not even coded as room entities.

The half Soul Heart was implemented properly in Afterbirth+, but the half Black Heart is still unused.

12 Room Charge

Image file: gfxuiui_chargebar.png

An unused charge bar variant for a 12 room charge space bar item. This graphic has been present since the original release, but was finally used in the November 13th Afterbirth update for the Mega Blast item.

Heart Jar Expansion

Image file: gfxcharacterscostumescostume_rebirth_90_thejar.png

Unused charge images for The Jar, an item which currently caps at 4 collected hearts.

Breath of Life

Image file: gfxcharacterscostumescostume_breath of life.png

The Breath of Life item was supposed to have a different animation, and the graphics for it are still present in the game, but the actual animation has been dummied out. All but the last blue-tinted frame are copied from the Chocolate Milk item's charging animation.

The actual graphical effect for Breath of Life in the finished game is a gradual change of Isaac's skin tone, from perky pink to hold-my-breath blue.

Old Tinted Rocks

Basement Cellar Caves Catacombs Cathedral	Depths Necropolis Sheol	Secret Room

Image files: gfxgridrocks_[chapter name].png

Most of the chapter tilesets have earlier tinted rock graphics. These conspicuous tinted rocks are very similar to the ones used in the original game.

Dark Rocks

Basement	Cathedral

Image files: gfxgridrocks_[chapter name].png

Even darker rocks that are only in the Basement and the Cathedral. These were used in prototype versions of the game, and are early versions of the indestructible gray blocks seen in the final game.

Unused Tinted Obstacles

Basement	Cellar	Cathedral	Caves	Catacombs	Secret Room	Depths Necropolis Sheol	Womb Utero

Image files: gfxgridrocks_[chapter name].png

There are tinted versions of every chapter-specific obstacle, but none of them are used in the game. Interestingly, the images for The Catacombs and The Necropolis Steam achievements use these tinted variants.

Angel Boss Names

Image files: gfxuibossvsnames.png

Placeholder names for the two Angel bosses -- actually named "Uriel" and "Gabriel" in the game's entities2.xml configuration file -- for use on the Boss Vs. screen. Since the bosses are immediately spawned by bombing the angel statue, they don't get an intro and these names are never used or needed.

Florian Himsl's Credit

Image file: gfxcutscenesintro6.png

Florian Himsl is still on the intro image, right next to Edmund McMillen, but is never shown ingame.

Tear Cursor

Image file: gfxuicursor.png

By enabling the Mouse Cursor mode on the game's "options.ini", it shows the cursor with four arrows (the one on the left). The "classic" Windows cursor is never used.

Cage Vomit

Image file: gfxbossesrebirthboss_090_fatty2.png

In The Cage's spritesheet, there are several unused sprites that actually turn out to be the boss Mega Fatty's vomit-beams, only recolored. Due to the fact that The Cage doesn't necessarily have a head at all, this is possibly the reason why these sprites for one of the boss's attacks are cut out.

Afterbirth+ Room Editor

	Unused	Used
Mask of Infamy Heart
Small Mask of Infamy Heart
Camillo Jr.
Gurgling (Enemy)
Begotten
Mega Fatty
The Cage
Uriel
Gabriel
Fallen Angel
Closed Stone
Brimstone Eye
The Husk
Double Keys
Mega Satan

Image files: toolsRoomEditoricons

As the room editor was used by devs during development, early versions of some things in the game are still shown.

Steven's Gemini Leftover

Image file: gfxbossesrebirthboss_013_steven.png

As uninteresting as it is, it's still an unused leftover from Gemini.

Sisters Vis

Image file: gfxuibossbossname_sisterssvis.png

Image file: gfxuiachievementachievement_sistersvis.png

There is an entry for "Sister Vis" within Rebirth's boss name texture file. Sisters Vis also has an unlock screen texture and noted out achievement prerequisites.

<!-- beat Sheol 10 times -->

<!--<achievement id="179" text='You unlocked "Sister's Vis" in Sheol' gfx="Achievement_SistersVis.png" />-->

Sisters Vis was finally finished for the Afterbirth+ DLC, but they don't have to be unlocked, don't appear in Sheol, and are called "Sisters Vis" in the boss screen, not "Sister Vis."

Button

Image files: gfxgridgrid_pressureplate.png

This button/pressure plate was officially implemented in the Afterbirth update, but it's been coded and usable since day one.

This early version of the button acts like a test object for the room lock buttons and random spawn buttons in Afterbirth, though what the button spawns is different as well.

If there are any enemies in the room, the button can't be pressed -- this includes the flies that the button spawns.

Original Book of Belial

Image file: gfxuigiantbookgiantbook_006_bookofbeast.png

Found on the "giantbook" folder (on-screen animations that are shown when using certain items) contains the book from Book of Belial from the original game. The file name of the image has a different than the actual item.

Unused Gamma Menu

Image file: gfxuimain menugammamenu.png

Graphics found on the main menu folder contains a more advanced gamma settings. In-game, you can only change the gamma and that's it, and pressing on the option won't cause the menu to change to another, since it's implemented inside the "Options" menu. It also has its own animation file.

Unused item on the Collection Page

Image file: gfxuideath items.png

On the collection page image, the last item seems to be a "Missing Poster", however, the Missing Poster is a trinket item in the game, so this icon is never seen on the Collection table or when the game is paused. Strangely enough, the item isn't found just next of the previous item in the sheet image, it actually breaks a line after the Dog Food (last item seen in-game via the menu).

Unused Exploded Doors

Image files: gfxgriddoor_[Floor Number]_[Floor Name].png

In game, when Isaac drops a bomb on a door, the door will explode and will load a different sprite (a burst door), letting the player skip the room. However, not all doors from all floors can be destroyed with bombs. In the game files, almost every (except the Devil Room door) single door has a burst sprite. This is likely a result to copy and paste data (since most of these has the "Basement" coloring scheme), not matching the special door associated it.

However, doors for "Curse Rooms", "Arcade Rooms" and doors from the "Chest" and "Dark Room" rooms have burst sprites, even though none of these are possible to explode. The Dark Room doors is actually a complete copy and paste from the Sheol Room, however the game loads the door_21_darkroomdoor and not the one from Sheol.
Images were cropped to only show the burst part of these sprite sheets.
In order: Curse Room, Arcade Room, Dark Floor Room and Chest Floor Room.

Unused Dice Room Door

Image file: gfxgriddoor_25_diceroomdoor.png

It seems that originally, the Dice Room door would have a red-ish scheme (somewhat similar with the color scheme from the Womb/Utero). This change was probably made for the player not know the existence of the room unless opening with two keys (in-game, both Library and Dice Rooms requires two keys to open, and the Dice Room does not have any special color, it uses the color from the current floor).

Unused Fistula Section

Image file: gfxbossesclassicboss_025_fistula.png

An unused section for Fistula. It fits between the medium and smallest sections.

Unused Peep Expressions

Image file: gfxbossesclassicboss_027_peep.png

Unused expressions for Peep.

Mega Satan Skeleton Hand

Image file: gfxbossesrebirthmegasatan2.png

A skeletal version of Mega Satan's hand. The hand never spawns in his skeletal form, rendering this unused.

Pony Forward Sprites

Image file: gfxcharacterscostumescostume_130_pony.png

Image file: gfxcharacterscostumescostume_181_whitepony.png

While not unused, these sprites are quite difficult to view it entirely due to Isaac's body and head covering it. It may become easier to see with items that removes his head or body.
In order: A Pony and White Pony.

Unused Floors

By disabling the invalid seed check and using an invalid seed, you can continue the game after the Chest and Dark Room, up to a whooping additional 14 floors! They use pre-existing graphics and the same layout.

A similar feature like this was added in the Afterbirth+ DLC, allowing you to continue the game multiple times after beating the Lamb.

Unused Item Pools

Two item pools are unused in the original game despite being defined in itempools.xml. Both pools can be seen in Afterbirth by picking up the "Chaos" item and using a restock box.

Blue items were added to the pools in Afterbirth.
Red items were added to the pools in Afterbirth+.

The first is labeled as "bossrush" internally, and contains bomb-related items. The actual Boss Rush room uses the Treasure Room item pool. This is not the same as the Bomb Bum's item pool, which is labeled "bombBum".

The second pool is labeled "dungeon" and might have been the original item pool for crawl spaces, which are labeled as "ROOMTYPE_ITEMDUNGEON" internally. All items are in some way related to Isaac's Mom.

Regional Differences

Title Screen

The style of the Japanese title screen is similar to the Japanese title screen of The Legend of Zelda: A Link to the Past.

	English	Japanese
Rebirth
Afterbirth

Secrets

Aside from the obvious change in language, the Korean secrets (in-game achievements) use different images for Cat Got Your Tongue and Everything is Terrible 2. Interestingly Ultra Greed has a beard like in early screenshots.

	English	Korean
Cat Got Your Tongue
Everything is Terrible 2

Unused Audio

The Binding of Isaac: Rebirth has some unused audio found with the help of Afterbirth+ modding tools.

Early Boss Rush Outro

An early outro for the track 'Ambush' played in the Boss Rush room.

Early Angel Room Appearance Jingle

Oldest version of the jingle that plays when an Angel Room appears.