The Binding of Isaac is the result of putting The Legend of Zelda, Smash TV, a roguelike, and a couple of dead baby jokes into a blender...and hitting Liquefy.

An expansion pack, Wrath of the Lamb, added more enemies, more levels, more items, more dungeon features, more bosses, more unused content, and more bugs.

Three years after release, a remake of the game was released, titled The Binding of Isaac: Rebirth.

Unused Sounds

Powerup_Zelda_Headlift

Unused Room Layouts

When Wrath of the Lamb was released, a lot of room layouts were added; in fact, a handful of rooms were added that are never able to be seen in-game! These rooms exist only in the flash assets and their ID values are never generated in-game, but Cheat Engine can be used to reveal them. They are all fully functional; they were either purposefully left out or (most likely) omitted due to an oversight during room generation.

Basement/Cellar

• Unused Basement rooms: B1, B2
  


• Unused Cellar rooms: B2
  

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  Basement Room B1
  

  
  

  
  


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  Basement Room B2
  

  
  

  
  


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  Cellar Room B2
  

  
  

  
  

Caves/Catacombs

• Unused Caves rooms: A9, AA
  


• Unused Catacombs rooms: AA
  

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  Caves Room A9
  

  
  

  
  


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  Caves Room AA
  

  
  

  
  


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  Catacombs Room AA
  

  
  

  
  

The Depths/Necropolis

• Unused Depths rooms: 9A, 9B
  


• Unused Necropolis rooms: 9B
  

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  Depths Room 9A
  

  
  

  
  


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  Depths Room 9B
  

  
  

  
  


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  Necropolis Room 9B
  

  
  

  
  

The Womb/Utero

• Unused Womb rooms: 89
  


• Unused Utero rooms: 89
  

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  Womb Room 89
  

  
  

  
  


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  Utero Room 89
  

  
  

  
  

Sheol/Cathedral

Surprisingly, there are 11 unused rooms for Sheol; however, all of these rooms save for one have an equivalent in the Cathedral that is used in-game. Some of them also appear to be similar to already existing Sheol rooms.

• Unused Sheol rooms: 52, 53, 54, 55, 56, 57, 58, 59, 5A, 5B, 5C
  


• Unused Cathedral rooms: 5C
  

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  Sheol Room 52
  

  
  

  
  


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  Sheol Room 53
  

  
  

  
  


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  Sheol Room 54
  

  
  

  
  


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  Sheol Room 55
  

  
  

  
  


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  Sheol Room 56
  

  
  

  
  


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  Sheol Room 57
  

  
  

  
  


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  Sheol Room 58
  

  
  

  
  


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  Sheol Room 59
  

  
  

  
  


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  Sheol Room 5A
  

  
  

  
  


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  Sheol Room 5B
  

  
  

  
  


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  Sheol Room 5C
  

  
  

  
  


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  Cathedral Room 5C
  

  
  

  
  

The Chest

• Unused Chest rooms: 06, 07
  

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  Chest Room 06
  

  
  

  
  


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  Chest Room 07