Secret Rooms

Secret rooms can be identified by looking out for "X" marks on the floor. Placing a bomb near the "X" will reveal stairs that lead to another room.

Not every floor contains one but in every run at least a few secret rooms can be found.

An example of a hidden secret room.

An example of a very well hidden secret room.

There is a perk that can be chosen in the Mastery Tree that adds sparkles to any hidden room making it much easier to see when they are present within a room.