Go back to this room. Remove the closet sideways. Smash the armour and make the ghost vanish. Find missiles, plasma gun ammo and a 1-up in the secret storeroom. You may need them later.

Find a cross, and a 1-up, behind these secret doors and the locked (brass) door.

Enter the dungeons. Finish with any remaining ghost or sub mutants. Enter the last cell, take the death chalice and follow the path to the gold key.

Find your way here. Take the two extra crosses. Enter the central ballroom.

Get ready for a final showdown with Zombie Hitler! Move quickly around the stone wall sections while fighting him. Collect missiles, plasma balls and gold chalices. Go back to other rooms for more ammo, health and 1-ups you may have saved. Finally defeated Zombie Hitler will leave you the iron key, and 3 x poison! Be sure you end up with more than 60% of health before taking the iron key!

Continue.