No menu, aperte lt e rt umas cinco vezes. Depois vá ao pc e digite:
Mission select, "Five" Zombies mode map, Dead Ops Arcade game, and Zork game
Enter "3ARC UNLOCK" as a code to unlock the "Five" Zombies mode map, Dead Ops Arcade game, Zork: The Great Underground Empire text-based adventure game, and all missions.

All Intel
Enter "3ARC INTEL" as a code to unlock all Intel. Note: Enabling this code will prevent the "Closer Analysis" achievement from being earned.

Alicia game
Enter "ALICIA" as a code to unlock the Alicia virtual therapist game.

Dead Ops Arcade game
Enter "DOA" as a code to unlock the Dead Ops Arcade game, which is a zombie killing mini-game similar to Smash TV. Use the Left Analog-stick to move and the Right Analog-stick to shoot. Note: Play the Dead Ops Arcade game to get the "Insert Coin" achievement.

Zork game
Enter "ZORK" or "HELLO SAILOR" as a code to unlock the Zork: The Great Underground Empire text-based adventure game. Note: Play the Zork game to get the "Eaten By A Grue" achievement.

Display all commands
Enter "HELP" as a code to display a list of system commands in the terminal and Pentagon user e-mail access.

Open corresponding file
Enter "CAT [filename]" or "PRINT [filename]" as a code to open the corresponding file.

List audio files and pictures
Enter "DIR" as a code to display a list of audio files and pictures for use with "CAT" command.

List of login names
Enter "WHO" as a code to display a list of login names for use with the "RLOGIN" command (requires passwords).

Login
Enter "LOGIN" as a code to login with a corresponding username and password.

Open mail folder for current user
Enter "MAIL" as a code to open the mail folder for the current user.

Display contents of current directory
Enter "DIR" or "LS" as a code to display the contents of the current directory.

Encode a string using the CIA's cypher
Enter "ENCODE" as a code to encode a string using the CIA's cypher.

Decode a string using the CIA's cypher
Enter "DECODE" as a code to decode a string using the CIA's cypher.

Display "Fee Fie Foe Foo!"
Enter "FOOBAR" as a code to display "Fee Fie Foe Foo!".

Há também a opção para acessar as contas dos militares do jogo:

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