A Corridor is any Room that contains a Corridor. Corridors act as small hallways used to differentiate level layout. Corridors' open sides cannot be placed against another Corridor's closed side.
A Transition Corridor is a special type of Corridor that can be marked as an exit for Campaign Mode levels via the "Is Exit" checkbox. When players enter an exit for a Campaign Mode level it will trigger the end of the level and take players to the Next Level if that value has been set.
A Standard Room is any Room that does NOT contain a corridor. These Rooms are larger and usually make up most of a level's Rooms.
Walls are placed between Rooms. Regardless of what wall settings you choose when making a new Standard Room, the outside edges of your level will always auto-gen full walls. When you place a Standard Room next to a Corridor, the Standard Room's wall will be adjusted to match the Corridor's side. When placing a Standard Room next to another Standard Room, the neighboring Standard Room's wall will be adjusted to match the Standard Room being placed. When placing a Corridor next to a Standard Room, the neighboring Standard Room's wall will be adjusted to match the Corridor's side.
When changing walls in a Room, all Doors bordering that Room will be removed.
Walls have an option to override their style with FadeAway walls. This can be used to indicate the edge of a level that would not be walled in.