Each floor of the game is made up of a number of rooms. The number of rooms on each floor generally increases as the game progresses.
- 1 Normal Rooms
- 2 Special Rooms
- 2.1 Boss Rooms
- 2.2 Treasure Rooms
- 2.3 Shops
- 2.4 Arcades
- 2.5 Challenge Rooms
- 2.6 Curse Rooms
- 2.7 Sacrifice Rooms
- 2.8 Secret Rooms
- 2.9 Super Secret Rooms
- 2.10 Libraries
- 2.11 Devil Rooms
- 2.12 Angel Rooms
- 2.13 Vaults
- 2.14 Dice Rooms
- 2.15 Bedrooms
- 2.16 Crawl Spaces
- 2.17 I AM ERROR
- 2.18 Boss Rush
- 2.19 Final Boss Room
- 2.20 Blue Womb
- 2.21 Closets
Normal Rooms make up the majority of the rooms on a floor. These rooms typically contain enemies and may drop a pickup or chest after all enemies are killed. Many rooms also contain various pickups, chests, items, and obstacles.
Isaac cannot leave a room with enemies until they are all killed or until he uses a bomb to open a door. If Isaac is currently holding an active item, completing a room with enemies will add one charge.
Rooms can come in various sizes; while normal-sized rooms are the most common, double and quadruple-sized rooms can also appear.
L-shaped triple-sized rooms, narrow hallways, and tiny rooms can also appear. Additionally, completing a quadruple-sized room or an L-shaped room will add two charges to Isaac's active item.
Mini-Boss Rooms are identical in appearance to normal rooms and contain one of the Seven Deadly Sins.
A Treasure Room, or Item Room, is guaranteed to appear on all floors From Basement 1 to Depths 2. From Basement 2 and on, this room requires a key to enter. The room can contain enemies and one item from the Treasure Pool. Various obstacles may be present.
Shops sell various items in exchange for coins. Shops start at level 0 and only sell 2 items, but shops at higher levels sell more items. They can be upgraded through the Donation Machine, which can be commonly found in the shops and sometimes in an Arcade. Shops also have a chance of being replaced by a miniboss room containing Greed or Super Greed.
These rooms are locked and require one coin to be opened. Arcades can only spawn on even floors (Basement II, Caves II, Depths II, Utero II) or XL floors if the previous floor was completed with 5 or more coins. Arcades can contain Machines, Beggars, and other objects.
Normal Challenge Room
Challenge Rooms can only be entered if Isaac's total health (red, black, and soul hearts) is equal to or greater than his number of heart containers. Upon picking up its contents, Isaac has to fight three waves of enemies.
Boss Challenge Rooms can only be entered if Isaac has one or less red heart. Its contents are similar to the normal Challenge Room, but upon picking up its contents, Isaac has to fight two waves of Bosses instead of normal monsters.
Curse Rooms feature spikes on the door that hurt Isaac when entering and exiting the room. Curse rooms can contain various things, ranging from enemies to items.
Sacrifice Rooms have a chance to spawn a chest after Isaac damages himself on the spikes featured at the center of the room. Sacrifice Rooms can pay out with a much wider variety of rewards.
Super Secret Rooms must be bombed into, and are only located next to one other room. Super Secret Rooms can contain a variety of pickups.
Dice Rooms require two keys to open. Depending on the number imprinted on the large red die embedded in the floor, stepping onto the center of the die activates an effect.
Bedrooms require two bombs to open. Bedrooms contain a bed that can be used once to restore all of the player's health, or if they have no red hearts they give you 3 soul hearts and fully recharge their active item. Depending on if the bedroom is clean or dirty, bombing the center of the carpet will reveal a Crawl Space or a trapdoor leading to the next floor.
These rooms are entered through trapdoors with ladders in them. They can rarely be found under destroyed rocks. They can also be found using We Need To Go Deeper!, Ehwaz, or in a clean Bedroom. These rooms are viewed from the side, rather than the top like the rest of the rooms in the game. Crawl Spaces usually contain an item or various pickups. Rarely, the Crawl Space will lead to a Black Market.
Black Markets are accessed through Crawl Spaces. These rooms are 2 rooms wide and have 5 shop items that can all be bought for 1 heart container. Black Markets also contain a trapdoor to the next floor and various machines or beggars.
I AM ERROR rooms have a small chance of being reached upon teleporting. Every I AM ERROR room contains a trapdoor to the next floor along with various pickups or items. The only way out of an I AM ERROR room is through this trapdoor or by teleporting out.
If the player manages to beat Mom in under 20 minutes (visually indicated by the clock icon that appears during the cutscene between floors), a crack will open in the wall of the boss room upon defeating her, allowing entry to a large room with 2 or 4 item pedestals in the center. Taking one of the four presented items will begin the Boss Rush.
Final Boss Room
This room is only found in the starting room of The Chest and The Dark Room. Opening this door requires Dad's Key or the two key pieces from Angels. Once the room is entered, Isaac will have to face off against the final boss, Mega Satan.
If the player manages to beat Mom's Heart or It Lives in under 30 minutes (visually indicated by the clock icon that appears during the cutscene between floors), a crack will open in the wall of the boss room upon defeating it, with a trapdoor to the Blue Womb.
Closets are rare, small, dead end rooms. They will often contain a unique arrangement of items, objects, or pickups.
|Achievements||Attributes||Bosses||Cards and Runes||Challenges||Chapters|
Boss Challenge Room
Super Secret Room
I AM ERROR