BACKROOMS SURVIVAL DIFFICULTY CLASSIFICATIONS; CLASS HABITABLE; CLASS 0; CLASS 1; CLASS 2; CLASS 3; CLASS 4; CLASS 5; CLASS 5E; COMPLETELY SAFE =); CLASS UNDETERMINED; CLASS DOLLFACE; CLASS Ψ; CLASS RHO; CLASS PARADISE; CLASS GET WICKED; CLASS HUNTING GROUND; CLASS CONTESTED [NON-HUMAN]; CLASS DEADZONE