invincibility (self)
Pause the game and select the "Cheats" option, then press X(2), A, B, A at the cheat menu. Press Back to resume the game. Your first soldier will be invincible, but the remaining members of your platoon can still be harmed in single player mode. Note: You cannot complete the game normally when this code is active, as maps and dossier items can no longer be unlocked. Also, this code can be activated without first completing the single mission dossiers.

Cheat mode
Successfully complete all objectives in the single mission dossiers. The following codes can now be enabled:

Big heads
Pause the game and select the "Cheats" option, then press A, X, B, Y, A at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear.

Big bodies
Pause the game and select the "Cheats" option, then press B(2), Y, X(2), A at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear.

Chicken explosives
Pause the game and select the "Cheats" option, then press X(2), Y, A, B at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear.

High pitched voices
Pause the game and select the "Cheats" option, then press X, A, Y, B, X at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear.

Paper mode
Pause the game and select the "Cheats" option, then press B, A, X, Y, A at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear. Characters will be two dimensional in this mode.

Run fast mode
Pause the game and select the "Cheats" option, then press A(2), X, B, Y at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear.

Slow-motion mode
Pause the game and select the "Cheats" option, then press Y(2), B, X, A at the cheat menu. Press Back to resume the game. If you entered the code correctly, a message will appear.