All weapons

Pause the game, then hold L1 and press Right, Circle(2), Triangle, Circle. If you entered the code correctly, a message will appear. Note: Only weapons normally available in the current level will be unlocked.

Invisible mode
Pause the game, then hold L1 and press Up, Left, Right, Up, Circle. If you entered the code correctly, a message will appear.

Slow-motion mode
Pause the game, then hold L1 and press Left, Down, Up, Right, Circle. If you entered the code correctly, a message will appear.

Fish eye camera
Pause the game, then hold L1 and press Left, Up, Right, Down, Circle. If you entered the code correctly, a message will appear.

Beagle holes, footprints, and burns
Pause the game, then hold L1 and press Down, Up, Circle, Triangle, Circle. If you entered the code correctly, a message will appear.

Alternate fade
Pause the game, then hold L1 and press Right, Up(2), Down, Circle. If you entered the code correctly, a message will appear.

Alternate lighting
Pause the game, then hold L1 and press Up, Right, Up, Down, Circle. If you entered the code correctly, a message will appear.