Im pretty sure im goin to make it work where when you press down near a window with zombies in it you'll hear a gun sound and it'll teliport you to the same map but i'll switch the windows...
once all of them are gone, the HELL room will open up... then the upstairs but when your done killing all of them upstairs, it'll warp you to the second nazi zombies map... the zombie asylum one.
then shi no numa...
then der reich...
i just made a little more so you can check it out.