Zombie Maps:
1. "Kino Der Toten" - The first map is given to you. You do not need to unlock the Nazi Zombie Mode by beating the campaign. You just access it through the main menu.

2. "Five" - The second map is unlocked when you beat the campaign.

DEAD OPS ARCADE:

3. "Dead Ops Arcade" - The third map is quite tricky to unlock. You will be looking at a TV in the Main Menu. With the RS Stick, move your head downward until you see your wrists. Pull and Press the Left and Right Triggers rapidly until you can stand up. Next, walk towards the back of the room until you find a computer. The computer will pull up a command prompt and ask for a password. The password is "RUSALKA." Next, type in "CD" and press Enter. Then, type in "DOA" and press Enter. Then play and it will be unlocked.


This works for xbox 360, ps3 and potentially pc as well.


WHAT IS DEAD OPS ARCADE?
Dead Ops Arcade is a Grand Theft Auto I, Top-Down 2-D Shooter. It's zombies but classic arcade/snes side scrolling type style. You use your right analog stick to whichever direction you want to fire your weapon(s). Lots of insane powerups, even the RayGun! haha. Be sure to check it out!