Level select
At the main menu, press and release L1 + L2 + R1 + R2 + Up. Press Circle to start a new game. From the difficulty menu, press L1 + L2 + R1 + R2 + Down. Choose a difficulty and the level select menu will appear.

Fart sounds
Highlight a game from the load game menu. Then, press L1 + L2 + R1 + R2. Exit the load game menu. Now levels with the Butthead monster will be modified by the code.

Full inventory
While playing a game, press Square + Select to enter 3D map mode. Press Left until the map arrow points toward you, then press Start to return to standard map view. Press L1 + Square + X + Circle while the camera is rotating. Press Select to exit Map mode. Press Triangle and for all the weapons and the jetpack.

Full ammunition
While playing a game, do a back flip by pressing Square + L2. Then while in the air, press Right + X + Circle. Now the ammunition for all weapons will be returned to full.

Full health
While playing a game, do a back flip by pressing Square + L2. Then while in the air, press Down + X + R2. Now Ox's health will be returned to full.

Invincibility
Use the full inventory code or find the drill to place it in inventory. Use the frying pan as the current weapon. Enter the weapon selection screen and highlight the drill, then press Circle + R1. If you entered the code correctly, the number "999" will be flashing next to the health meter.

Disable invulnerability
Enter the weapon selection screen and press Circle + R1.

View ending sequence
Save at least one game. Then, go to the main menu and highlight "Load Game". Hold Right, then press Circle. Release Right and press Triangle to cancel. Next, press Left + Square, then press Triangle to cancel again. Now the ending sequence will be displayed.

Disable no collisions
Switch to jetpack mode and press Triangle to display the weapon select screen. Then, press L1 + Right + Down.

No collisions
Switch to jetpack mode and kill an alien. Stand on the alien and press Triangle to display the weapon select screen. Then, press L1 + Right + Down. Now Ox will be able to fly through the walls and move anywhere in the level.