Syphon Filter

You never die : Pause and press and hold left + L2 + R2 + O + Triangle + Square at the same time. Then go to the options menu and select Cheats Menu.

All Weapons and Infinite Ammo:
Pause the game and highlight the Weapons menu. Press and hold Right + L2 + R2 + Circle + Square + X

Level Select:
Pause the game. Go into the Options menu. Highlight the Select Mission option. Press and hold Left + L1 + R1 + Select + Square + X

Easier Enemies:
Pause the game and highlight the MAP entry. Press and hold Right, R1, L2, X.

Harder Game:
At the title screen press and hold Left, L1, R2, Select, Square, Circle, and X.

Super Pistol:
Pause the game, select WEAPONS and highlight 9MM. Press and hold Left, R2, Select, L1, Square, and X.

View All Movies:
Go to the movie theater in the first level. Pause the game, highlight MAPS, then press and hold Right, L2, R1, and X.