The Binding of Isaac: Rebirth (Windows)

Prerelease Info AfterbirthThe first DLC expansion for Rebirth. They didn't keep the old man! Afterbirth+Confusing name and all, this is the second DLC expansion, requiring Afterbirth. RepentanceThe third DLC expansion for Rebirth, requiring Afterbirth+. The time has come to repent. Repentance+The fourth and currently final DLC expansion for Rebirth, requiring Repentance. You can finally stop playing with yourself!

Developer Messages#

Hidden Message#

The following message found in resources/packed/readme.txt warns 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.

This message remains in all future DLC releases of the game, even the ones which include official unpacking tools.

Cutscene Placeholder Messages#

The file that stores information for cutscenes contains "temporary texts" that describe what is happening in most of the cutscenes. However, these are commented out. If you restore them and watch a cutscene in-game, a placeholder screen will appear instead of the cutscene, unless the cutscene itself had no temporary text to begin with. The screen displays a description on a dark gray background that fades to light gray.

Source: resources/cutscenes.xml

Unused Rooms#

These are rooms that are not associated with any floor, so they will never be encountered. These rooms still exist in later DLC releases and can be accessed with the debug console in Repentance, with goto s.default.0 and s.default.1

DEFAULT_0 test room#

Room Type: DEFAULT
Room ID: 0
Room Name: test room
The first room in the game by ID. Contains 12 random items and 8 random trinkets.

Source: resources/rooms/00.special rooms.stb

DEFAULT_1 New Room#

Room Type: DEFAULT
Room ID: 1
Room Name: New Room
The second room in the game by ID. Contains four Gaping Maws and many spikes.

Source: resources/rooms/00.special rooms.stb

Unused Objects#

Button#

Image files: \gfx\grid\grid_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.

Unused Graphics#

Grid Objects#

Early Tinted Rocks#

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

These textures were removed in Repentance and replaced with spiked rock debris.

Basement Cellar Caves Catacombs Cathedral	Depths Necropolis Sheol	Secret Room

Unused Tinted Obstacles#

There are tinted versions of every chapter-specific obstacle, but none of them are used in the game. Some spritesheets simply use flipped versions of the regular obstacles in this space. Interestingly, the icons for The Catacombs and The Necropolis Steam achievements use these.

Tinted Skulls were later used in the Repentance DLC, though they look and function differently and are only used in Depths, Necropolis, and Dank Depths.

Basement	Cellar	Cathedral	Caves	Catacombs	Secret Room	Depths Necropolis Sheol

Early Indestructible Rocks#

Early versions of the indestructible rocks, used in prototype versions of the game.

These sprites were removed in Repentance.

Basement	Cathedral

Items & Pick-Ups#

The Jar#

Rebirth	Afterbirth

The Jar has frames for holding up to a whopping 10 hearts!

These frames were updated in Afterbirth, but removed in Afterbirth+'s Booster Pack 5 update.

Source: resources/characters/costumes/costume_rebirth_90_thejar.png

Breath of Life#

Breath of Life initially had a different animation, almost exactly alike to Chocolate Milk's effect. However, this animation has one frame of Isaac holding his breath that isn't found in Chocolate Milk's spritesheet. It has its own .anm2 file, paralleling Chocolate Milk's, and was given a gray skin-tone spritesheet in Afterbirth+. The finished effect for Breath of Life is a gradual change of Isaac's skin tone, from perky pink to hold-my-breath blue. This was assigned to Breath of Life in costumes.xml, but is commented out.

Sources: resources/characters/costumes/costume_breath_of_life.png, resources/characters/costumes/costume_breath_of_life_(COLOR).png

Sideways Headless Baby#

The Headless Baby familiar has sprites for it facing sideways, and even associated floating animations in its anm2 file. In game, it is always facing the camera regardless of what direction the player is moving in or firing.

Source: resources/gfx/familiar/familiar_shooters_269_headlessbaby

The Polaroid Trinket#

A sprite for The Polaroid exists in the directory containing trinket sprites. This is a leftover from the original Binding of Isaac, where The Polaroid was a trinket. Aside from being shifted 1 pixel up and to the right, it is identical to the item version's sprite.

Source: resources/gfx/items/trinkets/trinket_047_thepolaroid.png

Half Black and Soul Hearts#

A half-heart version of the black and soul hearts. Half soul hearts were added in Afterbirth+, but half black hearts are yet to make an appearance.

Source: resources/gfx/items/pick ups/pickup_001_heart.png

'Giant Book' Animations#

Original Book of Belial#

Image file: \gfx\ui\giantbook\giantbook_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 name than the actual name used for the item (in both the original Isaac and Rebirth). This was later implemented in Repentance.

Flush#

The Flush item originally had an image to appear after using it. This was implemented in Repentance.

Doors#

Unused Exploded Doors#

Curse Room	Arcade	Dark Room	Chest

Image files: \gfx\grid\door_[Floor Number]_[Floor Name].png

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

However, the doors for Curse Rooms, Arcades, and the standard doors in the Chest and Dark Room have graphics for being destroyed, even though none of these are possible to destroy. The Dark Room doors are actually a complete copy-paste of the doors in Sheol, but the game loads door_21_darkroomdoor, not the one from Sheol. Images were cropped to only show the burst part of these sprite sheets.

Unused Special Room Doors#

To do: Add an image of the Repentance Dice Room door for comparison.

Library	Dice Room

Image files: \gfx\grid\door_13_librarydoor.png, \gfx\grid\door_25_diceroomdoor.png

It seems that originally, the doors for the Dice Room would have had a red-ish color scheme (somewhat similar to the color scheme from the Womb/Utero). This change was probably made to prevent the player from knowing the existence of the room unless they open it with two keys (in-game, both the Vault and Dice Room require two keys to open, and the doors they use look identical).

A special door graphic was later given to the Dice Room in Repentance, though it looks significantly different from the one used here.

Enemies & Bosses#

Unused Hive Face#

Image file: \gfx\monsters\classic\monster_130_hive.png

An unused Mulligoon-like face for the Hive enemy.

Mulliboom Self-Destruct Animation#

Image file: \gfx\monsters\classic\monster_061_mulliboom.png

An unused self-destruct animation for the Mulliboom enemy, copied directly from Mulligan. Mullibooms never self-detonate in-game.

Unused Fistula Section#

Image file: \gfx\bosses\classic\boss_025_fistula.png

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

Unused Peep Expressions#

Image file: \gfx\bosses\classic\boss_027_peep.png

Peep has sprites which contain just the head without being obscured by arms, but these are never used ingame as its body sprites already have its head included.

Cage Vomit#

Image file: \gfx\bosses\rebirth\boss_090_fatty2.png

In The Cage's sprite atlas, 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.

Steven Umbillical Cord#

Image file: \gfx\bosses\rebirth\boss_013_steven.png

Steven's spritesheet still has a remnant of Gemini's umbillical cord, which has been recolored black. This is never seen ingame, as Steven doesn't have a cord.

Sisters Vis#

Image file: \gfx\ui\boss\bossname_sisterssvis.png

Image file: \gfx\ui\achievement\achievement_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&apos;s Vis" in Sheol' gfx="Achievement_SistersVis.png" />-->

This boss was added as a Chapter 3 boss in Afterbirth+, but are unlocked with the other Afterbirth+ bosses, don't appear in Sheol, and are called "Sisters Vis" in the boss screen, not "Sister Vis."

Miniboss Names#

Image files: \gfx\ui\boss\vsnames.png

Placeholder names for the two Angel minibosses—actually named "Uriel" and "Gabriel" in the game's entities2.xml configuration file and in the Bestiary in the Afterbirth+ DLC—, as well as Krampus, for use on the Boss Vs. screen. Since these minibosses spawn immediately by bombing angel statues or, in the case of Krampus, having a chance to appear in a Devil Deal, they don't get an intro and these names are never used nor needed.

Mega Satan Skeleton Hand#

Image file: \gfx\bosses\rebirth\megasatan2.png

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

Miscellaneous#

Florian Himsl#

Image file: \gfx\cutscenes\intro6.png

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

Unused Gamma Menu#

Image file: \gfx\ui\main menu\gammamenu.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: \gfx\ui\death 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).

Tear Cursor#

Image file: \gfx\ui\cursor.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.

Boss Frame#

Image file: \gfx\ui\frame.png

A basic debug frame used to assist designing the boss intro screens.

12 Room Charge#

Image file: \gfx\ui\ui_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, as well as items in later DLCs which have a 12 room charge.

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 Afterbirth+, allowing you to continue the game multiple times after beating The Lamb.

Unused Item Pools#

A few unused item pools exist, some of which have existed since Rebirth. Despite being unused, these item pools have been updated in each DLC. All of these pools can technically be enabled in Afterbirth and onward by picking up the Chaos item.

Key: Rebirth, Afterbirth, Afterbirth+ Repentance

Source: resources/itempools.xml

bossrush#

An item pool containing bomb related items. Removed in Repentance, and its numerical ID used for that DLC's "batteryBum" item pool.

dungeon#

An item pool containing Mom and food related items. Removed in Repentance, and its numerical ID used for that DLC's "momsChest" item pool.

Unused Audio#

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

Challenge Room Jingle#

An unused jingle that was meant to play when entering a challenge room for the first time, similar to the original game.

Early Angel Room Appearance Jingle#

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

Version Differences#

Wii U#

• The game's map can be displayed on the Wii U GamePad with the Select Button.
• Due to a bug, the intro to the Caves music is different, despite the internal sound data being the same as on PC.

• Using the Book of Belial when fighting Mega Satan crashes the game.

New 3DS#

• The bottom screen features the map (along with all-new art for all active items), and lets you draw on the map using the stylus.
• If unlocked, The Lost starts with the D4 in this version.
• Only in the Korean version, The Lost has spectral tears (but no D4 or Holy Mantle).
• The file options.ini is still present, located in the save file. However, most of the options do not work properly, like the fullscreen one.
• In the Korean version, you can still revert the game to English changing the options.ini file. This, for some reason, gives back the D4 to The Lost with spectral tears, making this the best version of The Lost.
• Strangely, the eraser option of the map functions incorrectly, drawing a bigger line instead of deleting it. This is changed in the Korean version, where the eraser actually erases the traces made.

PC	International 3DS	Korean 3DS

• The drawing showed in the map during the Curse of the Lost or Amnesia pill is different between versions. The Korean one is a tiny and pixelated question mark and the other versions is a bigger and less pixelated one. In fact, the Korean one is the same as the PC.
• For some reason, the same happens with the hard mark and the no achievement mark, they are both the same as the PC one and way smaller in the Korean version compared to the other versions.

• If you exit the game with the menu and the map was drawn, when returning to the run, the drawings will have a lighter color. This is changed in the Korean version, where the color is always light and nothing happens when exiting and returning.

• The map opacity is changed to pen opacity. However, inside options.ini, it is still treated as map opacity. Changing it with the options.ini file can lead to a bug, where the traces are colored white if the limit of 1 is bypassed. This only works with the pen (the bugged eraser does not work with this).
• In the Korean version, there's an active cam option.
• Due to a bug, the pink champion version of Widow is colored gray.
• The darkness effects generated by Dark One and The Adversary can be removed by pausing the game.
• Co-op was removed, meaning the co-op baby unlocks are now useless.

PS4 / PSVita / Xbox One#

• The Steam Sale item was renamed to Steamy Sale.

References#