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.
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. Some rooms don't have enemies and can contain only hazards such as spikes. Many rooms can also contain predetermined spots where pickups, chests and rarely items will spawn. Usually these pickups are surrounded by pits, rocks, spikes and other things.
The player may not leave a room with enemies until he or she kills them all or uses a bomb to open a door. Rooms without enemies are always open but do not give item charge. Unlike the original game, rooms with one to three possible entrances can also appear, such as rooms with 2 sides surrounded with rocks. Randomly two or four normal rooms may combine to create a larger room.
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.
Any room on the map that isn't a special room has a chance to turn into a Mini-Boss Room. Mini-Boss Rooms 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 contains no enemies and one item from the Treasure Pool. Various desctructibles 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. An Arcade can only spawn on an even floor (Basement II, Caves II, Depths II, Utero II), or an XL floor, if you exited the previous floor with 5 coins or more. Arcades can contain Blood Donation Machines, Beggars, and Slot Machines, and other objects.
Normal Challenge RoomEdit
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. Picking up its contents will spawns 3 waves of enemies when opened.
Can only be entered if Isaac has one or less red heart. Its content is similar to the Normal Challenge Room with the only difference being that Isaac has to fight against Bosses as opposed to normal monsters. The bosses are only spawned when Isaac opens one of the chests in the room.
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 will spawn a Chest upon Isaac damaging himself one or several times on the spikes featured at the center of the room.
Secret Rooms must be bombed into, and are located next to more than one room, usually 3 rooms, if not then 4, then finally 2, then one.
Super Secret Rooms are only located next to one other room, and this room can't be a special room (item, shop, boss,...). Also, the entrance of the Super Secret Room must be directly accessible (no rocks nor gaps in the way).
Libraries contain at least one book, card or rune in them. The books are free to pick up, but as they are all activated items, you can only take one.
These rooms, like in the original Binding of Isaac, allow the player to make deals with the devil by trading health for items. Sometimes red chests, black hearts or spikes will spawn instead of or in addition to items.
Angel Rooms feature an angel and several free items: the divine equivalent of the Devil Room. Every time the Devil Room is spawned, there's a chance to be replaced by the Angel Room if certain conditions are met.
Double Lock/Boarded RoomsEdit
These rooms are either locked by 2 padlocks or wooden boards. They need two keys or bomb explosions respectively to get in.
They can contain the following rooms:
Found in the Double Lock Room. Dice Rooms randomize many aspects of the game, depending on the number imprinted on the very large red die embedded in the floor. Stepping onto the center of the die activates its effect.
The Bedroom is located behind a double plank door requiring two bombs to open. In it is a bed that, when slept in, will restore all of the player's health and fully recharge their spacebar item, but can only be used once. Bombing the carpet will reveal a trapdoor, leading to the next floor, or a trapdoor with a ladder, leading to a Crawl Space.
These rooms are entered through trapdoors with ladders in them, as opposed to trapdoors without ladders which lead to the next floor. Ladder can often be found either under a bedroom rug, are sometimes created when using We Need To Go Deeper! item or very rarely from under destroyed rocks. Occasionally, you will find that the Crawl Space will lead to a Black Market. These rooms are viewed from the side, rather than the top like the rest of the rooms in the game.
Black Markets are accessed through a Crawl Space. The rooms are 2 rooms wide and usually have 5 items that can all be bought for 1 heart.
This room is reachable at random by using a Telepill or Undefined.
Every I Am Error Rooms contain a trapdoor to the next floor. The only way out of an I Am Error Room is through this trapdoor or through the use of a teleport
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 Mom boss room upon defeating her, allowing entry to a large room with 4 item pedestals in the center. Taking one of the four presented items will begin the Boss Rush.
Final Boss RoomEdit
This room is only found in The Chest and The Dark Room. It is found only in the spawn room at the top. It has the appearance of a large treasure room door with a place for a key in the center. Opening this door requires either the two key pieces from Angels or Dad's Key. Once the door is open and you are inside you will have to face off against the final boss, Mega Satan. Template:MasterNav
Boss Challenge Room
Super Secret Room
I AM ERROR