Floor 1 - Dungeon door, Raal, Sisters
Floor 2 - Literally 2nd floor of the dungeon
Floor -1 - The Cellar
Floor -2 - The Catacombs
Floor -3 - The Rupture (or Gorak Tul)
Don't go the right room on the 1st floor for any reason! Wave 5 and wave 11 can be interchanged with the Floor (-1) and Floor 2, after you completed Gorak Tul.
Click Lucille Waycrest on the way to the top of The Rupture to go back to the initial of the dungeon; Go through the top of The Rupture, you will reach a dark teleport. Go cross it to go back to the Catacombs if you want to finish the ememies of the Floor (-1)
IF YOU GO FOR 25+, DO NOT TRY THIS ROUTE.