Swaps the layers with the Main tracks, and vise versa, meaning that the layer will play for the rest of the floor, while the main theme adds intensity when your in a room with at least 6 enemies.

This is the Afterbirth version of this mod, and will now also swap the Afterbirth tracks of their layers and mains, with the acceptation of one track though, but that's mostly because you don't here its layer that often :|

Any who... Enjoy ^_^