Instructions
Select "Multiplayer" from the main menu and then select "Nazi Zombies." Select "Verruckt" as your level of choice and enter a match with one friend. Your friend can play via splitscreen or your respective consoles' online gaming service.
Kill at least 10 waves of zombies to accrue points. With these points you can purchase new weapons and open doors within the level, thereby granting access to new locations.
Spend your points to open every door on the second floor of the map. Make your way to the room with the broken wooden floor in the northeastern corner of the second floor.
Kill all zombies in the current wave except for one. Allow the zombie to kill you in the center of the room.
Direct your partner to kill the zombie (thereby reviving you and ending the current wave), look at the broken wooden floor and jump up and down repeatedly. Because of a glitch in the game code, you will respawn in the room below.
Direct your partner to sacrifice himself to a zombie from the new wave. Once your partner dies, he respawns with you in the room below the broken floor.
Crouch in the corner of the room just below the bombed-out window.
Direct your partner to jump onto your crouched form and out of the window. Throw several grenades into the corner of the room to kill yourself and respawn beside your partner outside of the compound.