Rooms

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

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. The player may not leave a room with enemies until he or she kills them all or uses a bomb to open a door. 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.

Special Rooms

Boss Rooms

Boss Rooms require Isaac to face one of the game's bosses to earn an item and open a trapdoor to the next level. You either face one current-chapter boss in a normal-size room or two bosses of the last chapter in a larger room.

Treasure Rooms

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. Treasure Rooms will always contain one item from the Treasure Room pool. A Treasure room can be identified by the gold edges of the door.

Shops

There is a Coin Donation Machine at the back. The donations are stored across runs and can be retrieved, albeit at a loss, by using a bomb on the machine. Every time a bomb is used on the machine, the number displayed on it will be reduced, and the number of coin(s) minus 1 will spawn. After several donations, the Coin Donation Machine can become blocked and no more coins can be donated until the next run. The Steam Sale item makes all prices 50% less (rounding down for big purchases, and up for small items), and randomly the store will provide sales on some of their items without the Steam Sale item. Shops also have a chance of being replaced by a miniboss room containing Greed or Supergreed.

Coin Donation Machine Unlocks:

• 10 Coins - Blue Map (Item Unlock)
• 20 Coins - Lvl 1 (Upgrades the Store to Level 1)
• 50 Coins - There's Options (Item Unlock)
• 100 coins - Lvl 2 (Upgrades the Store to Level 2)
• 150 Coins - Black Candle (Item Unlock)
• 200 Coins - Lvl 3 (Upgrades the Store to Level 3)
• 400 Coins - Red Candle (Item Unlock)
• 600 Coins - (Lvl 4 Upgrades the Store to Level 4)
• 900 Coins - Blue Candle (Item Unlock)
• 999 Coins - Stopwatch (Item Unlock)
• 1000 Coins - Machine explodes dropping many coins (over 100) resets machine counter to 0 on next run

Potential Shop Items and Costs

• 3 Coins - Heart
• 5 Coins - Soul Heart
• 5 Coins - Bomb
• 5 Coins - Key
• 5 Coins - Battery
• 5 Coins - Pill
• 5 Coins - Tarot Card
• 15 Coins - Humbleing Bundle (makes all key, bomb, hearts, and pennies drop as pairs)
• 15 Coins - Steam Sale (takes 50% off all shop prices)
• 15 Coins - Deck of Cards (activateable: spawns a random Card)
• 15 Coins - The Jar (used as storage for Heart pickups)
• 15 Coins - Ladder (allows player to cross 1 space gaps)
• 15 Coins - Portable Slot Machine
• 15 Coins - Treasure Map (reveals entire floor)
• 15 Coins - Habit (Spacebar item gains a charge when Isaac is damaged)
• 15 Coins - The Compass (Shows all icons on the map)
• 15 Coins - Blue Map (reveals the secret and super secret room on map)
• 15 Coins - Converter (activateable: trades 2 soul/black Hearts for 1 filled Heart Container)
• 15 Coins - BFFS! (Improves familiars and orbitals)
• 15 Coins - Little Baggy (+1 pill space and drops a pill)
• 15 Coins - Magic Fingers (activateable:For 1 Coin damages all enemies in the room)

Arcades

These rooms are opened with one coin and can potentially contain:

• a Blood Donation Machine
• a Skull Game
• a Slot Machine
• a Key Beggar
• a Beggar
• a Devil Beggar
• a Donation Machine
• a random pickup
• a Fortune Telling Machine

Challenge Rooms

Normal Challenge Room

Possible to enter only if Isaac is at full health (not counting black/soul Hearts). Usually contains a chest that spawns 3 waves of enemies when opened. While in Chapter 4 (Womb/Utero) you will face three waves of bosses (usually bosses from Basement/Caves).

Boss Challenge Room

Possible to enter only if you have one or less full red heart container. Contains 1-3 chests of any kind. Causes 2 bosses to spawn with second one after the first one is defeated. After bosses are defeated an item from boss room pool is not spawned but an item from a regular room item pool might.
The bosses that spawn depend on which Chapter you are currently in:

• Basement: Monstro + Larry Jr.
• Caves: Chub + Peep
• Depths: Monstro II + Loki
• Womb: Fistula + Loki + Chub

Curse Rooms

Curse Rooms feature spikes on the door that hurt Isaac when entering and exiting the room. Floating Isaacs only take damage upon exiting the room. Curse Rooms can feature following things:

• Red Chests (most common)
• Stone chests
• Enemies, usually spiders. Defeating them counts as completing a normal room.
• Devil room item
• Blue fires.
• Black Hearts

Note: Curse of the Cursed will turn ALL doors except for special types into these type of doors.

Sacrifice Rooms

Sacrifice Rooms will spawn a Chest upon Isaac damaging himself several times on the spikes featured at the center of the room. Chest is guaranteed to spawn if damage on spikes would take you to half a heart total health. Sacrifice room has a high chance to contain a single heart item.

Secret Rooms

Secret rooms must be bombed into, and are located next to more than one room, usually 3 rooms. At least one dead body is located in every secret room which has a chance to spawn items or enemies when blown up.
Possible Spawns:

• Slot Machine
• Lost Contact
• An item from a secret area item pool.
• 1 Key and a Key Beggar
• 2 Keys
• 2 Bombs
• 3, 6 or 9 Coin pickups
• 3 Pills
• Battery
• Greed or super greed.
• Golden poop

Super Secret Rooms

Super Secret Rooms are only located next to one other room (but cannot border a special room) and contain different items.
Possible Spawns:

• 1 Black Heart

• Fortune Telling Machine
• 1 Eternal Heart

• Around 10 hearts (all hearts that are spawned in this room are full red hearts(even with humbling bundle))
• 5 pills
• A Dice Room

Libraries

A Locked Room entered using a key. Contains random books and tarot cards inside. May contain one or more items.

Miniboss Rooms

Miniboss rooms put Isaac into a fight against one of the 7 deadly sins in either their normal or super form (or against Ultra Pride).

Devil Rooms

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.

The devil room can be entered after a boss fight under certain spawn conditions which include chances based on not taking damage on a floor. You can also be teleported into the devil room using telepills, The Joker, or through red chests. If carrying a Goat Head, the Devil Room will always be spawned after the boss fight.

Devil rooms have a high chance to spawn if you take no red heart damage on the current floor, and appears in the boss room after it is defeated. Devil rooms spawning are also affected by the Sin stat give by certain items.

This is the list of pedestal items that can appear in a Devil Room.

Angel Rooms

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 you didn't make any deal with the devil before this boss fight. Angel Rooms have a high chance of spawning if you're carrying the Bible Tract, and even if you have already made a deal with the devil.
Possible drops include:

• x2 Eternal Heart
• x3 Soul Heart
• Rosary
• Aegis
• Holy Grail
• Holy Water
• Mitre
• The Wafer
• Trinity Shield
• Sacred Heart
• Breath of Life
• The Bible
• Guardian Angel
• Dead Sea Scrolls

After beating the Dark Room or the Chest once, you are able to break the pedestal which the Angel sits on, doing so will begin a fight. After the fight you are rewarded with a key piece item which has connections to the big Gold door in the Dark Room/Chest.

Double lock/boarded rooms

These rooms are either locked by 2 padlocks or wooden boards. They need two keys or bomb explosions respectively to get in.

Dice Rooms

Dice Rooms randomize many aspects of the game, depending on the number printed on the very large red dice embedded in the floor. Stepping onto this dice activates its effect.

This can only be done once per room.

If the dice shows a 1, it will re-roll the items you are carrying in an unknown way. (Could maybe be a Random reroll of the other 5 as well?)

If the dice shows a 2, it will re-roll all pickup items in the dice room.

If the dice shows a 3, it will re-roll all pickup items on that floor.

If the dice shows a 4, it will re-roll all items on the floor, including the ones in Item Rooms, Shops, and Libraries. This will NOT re-roll Devil Room items.

If the dice shows a 5, it will re-roll entire floor and restart it, a similar effect to the 'forget me now' item but without the loss of your current item

If the dice shows a 6, it will re-roll (or possibly just randomize) every item you are carrying, including all passive upgrades, as well as all pickup items on the floor.

In addition, dice rooms contain chests and items.

Bedrooms

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. Bedrooms need 2 keys or bomb explosions to get in. If the player has no red heart containers, it will add three soul hearts. This is a reference to Link's bedroom in The Legend of Zelda: A Link to the Past

Rarely, these rooms can have the bed covered in spikes, annulling any use.

Bombing the carpet will reveal a trapdoor, leading to the next floor, or a trapdoor with a ladder, leading to a Retro Treasure Room.

Miscellaneous double unlock rooms

Most of the time double unlock rooms containing the following:

• Several chests, sometimes behind rocks and/or locks. Possible combinations include 4 golden chests, 4 chests with 1 of each type etc.
• Coins, sometimes with things found in arcade room
• Very few items (for an example, a single penny and 2 spiders).

Retro Treasure Rooms

These rooms are entered through trapdoors with ladders in them. Ladder can often be found either under a bedroom rug or very rarely from under destroyed rocks. They consist of 2 ladders and a cache of treasures, be it pickups, items, or arcade machines. Occasionally, you will find that the Retro room 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, and look similar to the treasure rooms in Zelda 1. Inside, there is no map.

This room seems to be opened by bombing random rocks, occasionally from using We Need To Go Deeper!, or the carpet in the Bedroom.

This room does not replace the normal Item room if there is one, and entering the trapdoor does not immediately send Isaac to the next floor.

Black Markets

Black Markets are accessed through a Retro Treasure Room. The rooms are 2 rooms wide and usually have 4 items that can all be bought for 1 heart. These will not be devil room items. Additionally there can be three beggars on the right side of the room. There is a chance that the room contains a trapdoor to the next floor as well.

I Am Error Room

The I Am Error Room is reachable at random by using a telepill or the "undefined" item (% chance still unknown, see talk). All 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.

Possible Room layouts include:

• 2 golden poops with normal poop surrounding the room
• Some money (~15 coins) and 1 free item

Boss Rush Room

If the player manages to beat Mom in under 20 minutes (essentially being faster than the little clock that appears upon getting to a new floor), a crack will open in the wall of the mom boss room allowing entry to a very large room with 4 item pedestals. Once one is taken, all others will disappear and the player will face fifteen waves of Bosses containing 2 bosses each. The wave order and the bosses fought is as follows, regardless if the individual bosses have been unlocked yet.

• Wave 1: Blighted Ovum and Gurdy Jr.
• Wave 2: The Carrion Queen and The Wretched
• Wave 3: The Duke of Flies and Peep
• Wave 4: Loki and Blastocyst
• Wave 5: Steven and Gemini
• Wave 6: Larry Jr. and Fistula
• Wave 7: C.H.A.D. and Monstro
• Wave 8: Gurdy and Chub
• Wave 9: Monstro II and Gish
• Wave 10: Widow and Pin
• Wave 11: The Hollow and The Husk
• Wave 12: The Bloat and Mask of Infamy
• Wave 13: Famine and Pestilence
• Wave 14: War and Death (Boss)
• Wave 15: The Headless Horseman and The Fallen

If Mom appears as a Champion, every Boss in the Boss Rush Room will be a Champion, too.

Upon completing the Boss Rush Room, the player will earn another random item and unlock an achievement, depending on which character was used:

• Isaac: Isaac's Head or Mom's Bra
• Maggy: Maggy's Bow
• Cain: Cain's Other Eye
• Judas: Judas' Shadow
• Eve: Eve's Mascara
• ???: ???'s Only Friend
• Samson: Samson's Chains
• Lazarus: Missing No.
• Azazel: The Nail
• Eden: Undefined

Final Boss Room

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 Fallen 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. The room is a 2x1 rectangle with a pentagram in the center. Mega Satan will spawn at the top of this room, and the pentagram in the center will fill up with blood when he does.