Chapters/Basement

The Basement is the first floor in The Binding of Isaac, which takes the appearance of an unfinished basement, that possibly has brick walls. The final boss of the level is Little Ghost. The monsters "Indigenous" to the chapter are Flies.

Rooms

 * 1: The room will always appear once in this floor
 * 2: The room will always appear twice in this floor
 * Possible: There is a chance for this room to appear, usually due to certain criteria being met
 * *: This room can only appear due to a bug or special item
 * -: The room cannot appear in this floor.