Instructions
Start "Call of Duty: Black Ops." Press the "Start" button when prompted to go to the main menu. Do not make a selection yet.
Press the "L2" and "R2" buttons alternately. This causes your character to look around. This allows you to see that the main menu is actually in a room and you are looking at it from the perspective of a character strapped to a chair. Keep pressing the buttons until you break out of the chair. You can now walk around the room.
Examine the computer terminal behind the chair. You are prompted to enter a password.
Enter "DOA" or "3ARC UNLOCK" into the terminal. Entering "DOA" only unlocks "Dead Ops Arcade." Entering "3ARC UNLOCK" unlocks everything in the game, including "Dead Ops Arcade," "Five" and every campaign level. "Dead Ops Arcade" is a non-standard Zombies map that can also be unlocked. Instead of the normal first-person shooter (FPS) play found in the rest of the game, "Dead Ops Arcade" is an arcade-shooter mini-game.
Complete the campaign on any difficulty level. This is the actual method to unlock "Five." You do not need to complete this step if you unlocked it by entering "3ARC UNLOCK" into the terminal.