Boss Rooms contain a challenging fight! It will be against one of the many Bosses, with victory giving you an item from the Boss Pool, Hearts (depending on difficulty), and a trap door leading to the next level. However, there are exceptions.
- Double-sized boss room will require you to fight against 2 bosses from the previous chapter. Defeating them only gives you one item.
- The only exception to this is Mr. Fred who always is fought in a double-sized room.
- If you are afflicted with Curse of the Labyrinth, you will have to fight 2 separate Bosses. The first one will give you an item, but no trapdoor. You must defeat the second one to move on to the next level. Rarely, the Boss Rooms are separated, and only one of them will generate a Trapdoor to the next floor.
When you defeat a Boss, an entrance to a Devil Room or Angel Room can appear.
 Boss Room |
 Mini-Boss Room |
 Treasure Room |
 Shop |
 Arcade |
 Challenge Room |
 Boss Challenge Room |
 Curse Room |
 Sacrifice Room | |
 Secret Room |
File:Super Secret Room Icon.png Super Secret Room |
 Library |
 Devil Room |
 Angel Room |
 Vault |
 Dice Room |
File:Bedroom Icon.png  Bedroom |
File:Super Secret Room Icon.png I AM ERROR |
File:Super Secret Room Icon.png Boss Rush |
| File:Super Secret Room Icon.png Crawl Space |
File:Super Secret Room Icon.png Black Market | |||
