MAP01 to MAP06; subterranean/starport levels:
Level 1: Entryway
Level 2: Underhalls (Exit to secret level; Xbox only)
Level 3: The Gauntlet
Level 4: The Focus
Level 5: The Waste Tunnels
Level 6: The Crusher
MAP07 to MAP11; hellish outpost levels:
Level 7: Dead Simple
Level 8: Tricks and Traps
Level 9: The Pit
Level 10: Refueling Base
Level 11: ‚O‘ of Destruction!1
1: Known as Circle of Death on the intermission screen.
MAP12 to MAP20; city levels:
Level 12: The Factory
Level 13: Downtown
Level 14: The Inmost Dens
Level 15: Industrial Zone (Exit to secret level)
Level 16: Suburbs
Level 17: Tenements
Level 18: The Courtyard
Level 19: The Citadel
Level 20: Gotcha!
MAP21 to MAP30; inside hell levels:
Level 21: Nirvana
Level 22: The Catacombs
Level 23: Barrels o‘ Fun
Level 24: The Chasm
Level 25: Bloodfalls
Level 26: The Abandoned Mines
Level 27: Monster Condo
Level 28: The Spirit World
Level 29: The Living End
Level 30: Icon of Sin
MAP31 and MAP32; secret levels:
Level 31: Wolfenstein2 (Exit to super secret level)
Level 32: Grosse2