The Binding of Isaac: Rebirth (Windows)

The Binding of Isaac: Rebirth
Developers: Edmund McMillen, Nicalis Publisher: Nicalis Platform: Windows Released internationally: November 4, 2014 This game has unused animations. This game has unused areas. This game has unused playable characters. This game has unused code. This game has a hidden developer message. This game has hidden developer credits. This game has hidden development-related text. This game has unused graphics. This game has unused music. This game has unused sounds. This game has debugging material. This game has regional differences. This game has revisional differences. This game has a prerelease article

This article is a work in progress. ...Well, all the articles here are, in a way. But this one moreso, and the article may contain incomplete information and editor's notes.

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!

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. The Wii U version also seems to have leftovers from the other Console versions as well (PS4, PSVita, 3Ds, Xbox One). Secret rooms have a few weird variants that go unused. Libraries are coded to appear more often if a book item is picked up, but the flag is never set. Investigate. Azazel's How to Jump sprites are not used. Developer Tyrone Rodriguez has posted a number of mockups/pre-release images under the #IsaacRebirthDev hashtag.

The Binding of Isaac: Rebirth is a remake of the original 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

Prerelease Info

Afterbirth The 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.

Repentance The 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.

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.

ID	Ending	Description
1	Intro	N/A
2	Credits	Credits sequence.
3	Epilogue	N/A
4	Womb (Eden)	Isaac crawls into the big chest, and re-emerges as Eden
5	Womb (Rubber Cement)	Isaac finds Rubber Cement in the big chest
6	Womb (Noose)	Isaac finds a Noose in the big chest and hangs himself
7	Womb (Wire Coat Hanger)	Isaac finds a Wire Coat Hanger in the big chest.
8	Womb (Everything is Terrible)	Isaac gets pulled into the chest by mom's hand. Everything is Terrible.
9	Womb (Ipecac)	Isaac finds IPECAC in the big chest.
10	Womb (Experimental Treatment)	Isaac finds Experimental Treatment in the big chest.
11	Womb (A Quarter)	Isaac finds A Quarter in the big chest.
12	Womb (Dr. Fetus)	Isaac finds Dr. Fetus in the big chest.
13	Womb (???)	N/A
14	Womb (It Lives!)	N/A
15	Sheol	While Isaac looks at the chest, he cycles through all characters and shows a demonic form of himself. He goes into the chest and closes it from inside.
16	Cathedral	Isaac is seen reading the bible. He looks into the mirror and sees a demonic form of himself.
17	Chest	A bunch of polaroid photos from Isaac's childhoold are shown.
18	Dark Room	A telephone pole in front of Isaac's house shows a missing poster featuring Isaac.
19	Mega Satan	Isaac is inside the chest and randomly flashes from his normal form to a demon form.
20	Blue Womb	Chest with Isaac's remains. Isaac in a chest, his shadow transforms into a demon.
21	Greed Mode	Isaac dies and turns into a keeper.
22	The Void	N/A
23	Greedier	N/A

Source: resources/cutscenes.xml

Unused Rooms

These are rooms that are not associated with any floor, so they will never be encountered. These rooms 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 Graphics

Grid 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.

Effect	Approximate Chance
Nothing	35%
Spawn a random chest	29%
Spawn 6 Attack Flies	20%
Spawn 6 Troll Bombs	10%
Activate Curse of Darkness for the rest of the floor	3%
Spawn a random pickup	2%
Spawn 15 random coins	1%

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

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.

Basement Cellar Caves Catacombs Flooded Caves Cathedral	Burning Basement	Depths Necropolis Dank Depths Sheol	Secret Room

Unused Tinted Obstacles

There are tinted versions of every chapter-specific obstacle, but none of them are used in the game. 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.

Basement	Cellar	Burning Basement	Caves	Catacombs	Flooded Caves	Depths Necropolis Dank Depths Sheol	Cathedral	Secret Room

Early Indestructible Rocks

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

Basement	Cathedral

Items & Pick-Ups

The Jar Expansion

Prior to Afterbirth	Prior to Booster Pack 5

Prior to Booster Pack 5, The Jar had frames for holding up to 10 hearts! After the sprite was redone the second time in Booster Pack 5, these extra frames were removed.

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 even has its own .anm2 file, paralleling Chocolate Milk's. 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. 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

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

Card Frame

A frame for the card sprites with nothing in it is present in the spritesheet for the cards. Likely left in to allow for easier creation of card sprites

Source: resources/gfx/ui/ui_cardfronts.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 reimplemented as in Repentance.

Flush

The Flush item originally had an image to appear after using it. Also reimplemented in Repentance.

Doors

Unused Exploded Doors

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.

In order: Curse Room, Arcade, Dark Room, and Chest.

Unused Dice Room Door

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

Image file: \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

Unused expressions for Peep.

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's Gemini Leftover

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

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

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's Vis" in Sheol' gfx="Achievement_SistersVis.png" />-->

The Sisters Vis were finally finished and released in Afterbirth+, 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."

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.

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 existing pools can be enabled in Afterbirth and onward by picking up the Chaos item.

Key: Rebirth, Afterbirth, Afterbirth+ Repentance

Source: resources/itempools.xml

challenge

An item pool containing bomb related items. Removed in Repentance, and replaced with the currently unused "shellGame" item pool.

Boom!	Mr. Boom	Mr. Mega	Bobby-Bomb	Bomb Bag
Remote Detonator	Bob's Curse	Butt Bombs	Sad Bombs	Mama Mega!
Fast Bombs

bossrush

An item pool containing... even more bomb related items. Removed in Repentance, and replaced with the "batteryBum" item pool.

Boom!	Mr. Boom	Mr. Mega	Bobby-Bomb	Bomb Bag
Remote Detonator	Bob's Curse	Butt Bombs	Sad Bombs	Bomber Boy
Scatter Bombs	Sticky Bombs	Curse of the Tower	No. 2	Explosivo
Glitter Bombs	Fast Bombs

dungeon

An item pool containing Mom-related items. Removed in Repentance, and replaced with the "momsChest" item pool.

Lunch	Dinner	Dessert	Breakfast	Rotten Meat
Mom's Underwear	Mom's Heels	Mom's Lipstick	Mom's Bra	Mom's Pad
Mom's Eye	Mom's Bottle of Pills	Mom's Contacts	Mom's Knife	Mom's Purse
Mom's Coin Purse	Box	Mom's Key	Mom's Eyeshadow	Mom's Wig
Mom's Perfume	A Snack	Mom's Pearls	Mom's Box	Moldy Bread
Mom's Razor

shellGame

An item pool comprised of poop-related items.

Skatole	The Poop	Butt Bombs	No. 2	Brown Nugget
Dirty Mind

unused24

A placeholder item pool. Was later overwritten post release with the ultraSecret pool.

Sad Onion

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", which plays in miniboss rooms (or in the Boss Rush before Repentance).

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.

Wii U	Windows

• 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.
• 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.

Regional Differences

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 in the Korean versions of these images, much like in early screenshots.

	English	Korean
Cat Got Your Tongue
Everything is Terrible 2