Secret Room



Secret Rooms are rooms that are not normally visible on the map and must be bombed into to access. Regular Secret Rooms are usually located next to 2 to 4 rooms, while Super Secret Rooms can only be next to one room. Very rarely, the regular Secret Room may also be located next to only one room. Entrances to Secret Rooms will never have rocks or gaps in the way. Secret Rooms usually contain at least one shopkeeper. Secret Rooms stay open after bombing them.

Variations
The following room maps were made using Basement Renovator for cleaner viewing; note that all Urns you see will be Mushrooms when encountered in-game.

Standard
Starting from the second floor of Chapter 2 onward, Greed and Super Greed have a chance to replace Secret Rooms.

Alternate Variations
Secret Rooms in alternate chapters (,, , , , and ) differ from the standard layouts. Each alternate floor has 11 unique layouts (12 in ). Regular secret room layouts cannot appear on these floors.

Super Secret Rooms


Super Secret Rooms are only located next to one other room, and this room can't be a special room (item, shop, boss, etc.). Each Super Secret Room has set drops depending on the floor. Note that the type of Super Secret Room is not limited to certain floors it mimics (e.g. one can find a Womb-themed Super Secret Room in the Depths).

Super Secret Rooms are most likely to be found either at the end of a series of rooms that lead to a dead-end, or close to the boss room, such as the room right before the boss, if possible.

Greed Mode
In Greed Mode, Super Secret Rooms have different layouts.

Ultra Secret Rooms
Ultra Secret Rooms are special rooms that are not connected to any other rooms on the map. They can only be entered by using, Crystal Key, or  to get to a red room adjacent to it, or teleporting directly into it with , despite not being red rooms themselves. Ultra Secret Room doors are automatically open and do not have to be opened. If teleported into with the card, the pathway back to the rest of the level is also opened. All items generated in them will be from the Angel Room item pool.

Ultra Secret Rooms attempt to generate connected to two valid red room locations that are directly next to any non-red room on the floor. Standard methods of mapping such as and  do not reveal them, but they can be located by,  wisps with the  effect, or a. When found, they are marked by a red ? on the map.

Most often, there will be two red rooms which are adjacent to both the Ultra Secret Room and non-red rooms. These red rooms must connect to at least one unique non-red room. This mechanic is to help figure out the possible location of the Ultra Secret Room.

Additionally, all adjacent walls of the Ultra Secret Room must connect to a valid red room location.


 * In the event that no other valid location spaces, it is possible that only one red room connects the Ultra Secret Room and normal rooms.
 * It is possible for the Ultra Secret Room to generate such that it requires the player to traverse through at least two red rooms.

In the Mirrored World, The Ultra Secret Room will not contain any item.

Trivia

 * In the original The Binding of Isaac, Secret Rooms worked differently; if the player left a room after opening a Secret Room entrance, the entrance would disappear. To access the room again for any purpose, the player needed another bomb to reopen the entrance.

Seeds
927Q 481S (Secret Room above Treasure Room is not attached to any others) 2CC7 S7YG (Secret room is attached to only one room; located on the eastern wall in the most eastern room starting from the spawn room) 419H 1DQM ( in Curse Room on your left, use it on the right of the Curse Room and the Ultra Secret Room will open up)