Secret Room

**Secret Rooms** are rooms that are not normally visible on the map and are usually accessed by bombing a wall leading to them. Regular Secret Rooms are usually located next to 3 or 4 rooms, while **Super Secret Room**s can only be next to one room; they are placed on one of the dead ends generated on the map, similar to other Special Rooms. 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.

### Possible Layouts

Starting from the first floor of Chapter 3 onward, Greed and Super Greed have a chance to replace Secret Rooms.

###  Alternate Variations

Secret Rooms in alternate chapters (Downpour, Dross, Mines, Ashpit, Mausoleum, Gehenna and Corpse) differ from the standard layouts. Each alternate floor has 11 unique layouts (12 in Downpour). Regular Secret Room layouts cannot appear on these floors.

## Super Secret Rooms

**Super Secret Room**s are only located next to one other room, and this room can't be a Special Room; in other words, it is placed on one of the floor's dead ends, like any other Special Room. 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. Isaac can find a Womb-themed Super Secret Room in 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, and is particularly likely to appear near the Boss Room, as they are the second room type to be placed on a map during Map Generation, and are therefore placed far away from the room Isaac starts in. Because Shops are the third type of room generated, super secret rooms are also likely to spawn near the shop, and are likely to spawn in between the shop and the Boss Room.

###  Greed Mode Layouts

Greed Mode has its own set of Super Secret Room layouts.

## Ultra Secret Rooms

**Ultra Secret Room**s are special rooms that are not connected to any other room on the map directly. They are not revealed by most mapping effects (, etc.) and can only be revealed on the map with ,  wisps, and . They can be accessed directly by opening **Red Room**s adjacent to them using  or Red Key wisps, , , and : entering a Red Room next to the Ultra Secret room will reveal its position and automatically open the doorway leading into it. It can also be entered by teleporting to it using ; when teleported into, a pathway of Red Rooms back to the rest of the level will be opened automatically. Ultra Secret rooms contain items from the Ultra Secret Room item pool.

Ultra Secret rooms are most likely generated in spots that connect to 3+ non-red rooms through its adjacent red rooms (different squares in L rooms count as 2). They can be connected to 2 or 1 non-red rooms through its adjacent red rooms, but a specific 3+ room location is 11.5x more likely than a specific 2 room location, and 1 room locations being virtually impossible if there is a 3+ location available. If there is no 3+ room location available then a specific 2 room location is 11.5x more likely than a specific 1 room location.

Ultra Secret Rooms can't be connected to red rooms that connect to Secret Rooms, Super Secret Rooms, or Curse Rooms, and can't be in a location where any of its adjacent red rooms are invalid, such as next to a Boss Room (Boss Rooms in The Void can have red rooms next to them, but the Ultra Secret Room will never be connected to one), next to the sides of narrow rooms, or any room that can't have a red room opened on that specific side, however locations on the 13x13 border where a red room would normally open to an I AM ERROR room are allowed.

### Notes

* Generally, the best strategy for finding Ultra Secret Rooms is by checking a location that connects to at least 3 non-red rooms through its adjacent red rooms (in which all sides can have red rooms created, and isn't next to a Secret, Super Secret, or Curse Room), and if it's not in any 3+ locations, checking the spots connected to 2 rooms, then 1.
	+ When choosing which side to open from, the best way to increase your odds is to open the red room that connects to the highest number of other potential Ultra Secret Room locations.
		- However, there is also value in choosing to open a red room that connects to an otherwise hard-to-access room, such as a Boss Challenge Room.
	+ If the only remaining valid locations are connected to a single non-red room, it's just as likely for the Ultra Secret Room to be connected to the side of a single room as it is connected to a corner.
* Curse of the Maze can move a room in a way that prevents creating a red room that connects to the Ultra Secret Room.
* The doors of the Ultra Secret Room are opened automatically only when approached from the outside. If other rooms exist adjacent to it, the doors will not open from inside the Ultra Secret Room without bombing them or returning from the outside.
	+ Red Key or Cracked Keys must be used before the bombs, as otherwise explosions won't have an effect.
* The Ultra Secret Room can generate north of the Mega Satan door, despite not being able to create a red room there.
* In the Mirrored World, the Ultra Secret Room will be empty, same as any Special Room.
* It's possible for the Ultra Secret Room to not generate if there are no valid locations.

## Notes

* Secret Rooms are found by bombing the middle of a wall in a standard size room. For larger size rooms, divide the room mentally into the size of individual rooms to figure out where to bomb.
* One easy strategy to place the bomb correctly in large rooms is to position Isaac in a corner, walk along a wall, then place the bomb at the spot where the camera starts moving.
* For closet-size rooms, Secret Rooms will never be found by bombing the sides but may be found by bombing the wall at the end of the closet.
* Rooms adjacent to Secret Rooms will always have a clear, walkable path to the middle of the wall where Isaac can place a bomb. Secret Room entrances are never found in front of gaps, obstacles, spikes, or places that enemies spawned when the room was originally entered. Each room adjacent to a Secret Room must satisfy these requirements, so if one room near a suspicious gap in the map fails these requirements, then look elsewhere.
* Secret Rooms are equally as likely to be in a valid location with 3 neighbors, as it is with 4 neighbors. 2 neighbor locations are rare but possible, even when there are locations with 3+ neighbors available. 1 neighbor locations can only happen if there are no valid 3+ neighbor locations, and are very rare.

* opens all available entrances to both the Secret Room and the Super Secret Room. The I Can See Forever pill does the same for the floor on which the pill was used.  will play a howl sound effect when Isaac enters a room adjacent to a Secret Room or Super Secret Room, and  will hover over Secret Room entrances.
* Teleportation items can randomly teleport Isaac into Secret Rooms, and  will always teleport Isaac to the Secret Room.
* Secret Rooms are revealed on the map with , , , , , , or , but Isaac will still need to open their entrance.
* can be used to find Secret Rooms. The lack of Red door frame means a Secret Room could have generated on the other side.
* sometimes reveals Secret Rooms as it can travel through them.
* If Greed or Super Greed spawn inside a Secret Room, Isaac won't be able to exit it (like a Mini-Boss Room), but once the fight ends, all the exits of the Secret Room will be accessible.
	+ An exception to this is that Challenge Rooms and Boss Challenge Rooms will be inaccessible; the metal bars won't be removed from walls that lead to them after the fight concludes.
* Secret Rooms can exist next to all types of rooms except Boss Rooms, Super Secret Rooms, and other Secret Rooms; allowing certain restricted rooms to be entered.
	+ Even if Isaac has no Keys, it is possible to bomb into a locked Special Room should there exist an adjacent Secret Room. Leaving through the door will unlock the room without requiring a Key.
	+ It is possible to enter Curse Rooms without taking damage by bombing in from a Secret Room.
	+ It is possible to access Challenge Rooms even if Isaac doesn't meet the health requirements, but it is not possible to "steal" the items, as the hole will be blocked up as soon as the fighting stage begins.
* Secret Rooms of all types do not exist in the Ascent.
* Once  Corrupted Data is achieved (beating Delirium as  Tainted Eden), items that spawn in Secret Rooms have a chance to be "glitched" as if affected by .
* Super Secret Rooms replace the dead-end room that would require the 2nd most rooms walked through from the start room to access, and cannot be connected to the Secret Room.
	+ For reference, the Boss Room takes the dead-end room that would require the most rooms walked through, and the Shop takes the room that would require the 3rd most. This means that the Super Secret Room is equally as far or further from the start room than the Shop. It also means the Super Secret Room tends to be close to the Boss Room. Loops and large rooms connected to more than one room on any given side can tamper with this logic, however.
	+ Sometimes, the Boss Room will not be the furthest dead-end room; usually, in these cases, the Boss Room has one side blocked off and the Super Secret Room will be connected to the furthest normal room, with the wall leading to it being on the opposite side of the blocked off side in the Boss Room.
		- For example, if the blocked off side in the Boss Room is to the north, the Super Secret Room will be to the south of the furthest normal room.
* Super Secret Rooms can have layouts with themes from floors that Isaac hasn't unlocked yet.

## 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.
	+ For some reason, Challenge Rooms and Boss Challenge Rooms still work this way.
* Prior to V1.7.5, Ultra Secret Rooms used the Angel Room Item Pool. This was meant as a placeholder.

## References

1. ↑ https://github.com/Tempus/Basement-Renovator