Syphon Filter 1 shot kill with 9mm press start the go to the weapons and highlight 9mm. the press and hold left+L1+R2+Select+Square+X [send by:Eric] Level select[Sent by Evan] First pause the game and go in the options menu go to select mission and reaptively if it doesn't work the first time press and hold Left, L1, R1, select, Square, and X Movie Theater[Sent by Steak] Go into the building where Kravitch is located in the first level (Georgia Street). After killing the first enemy in that building before Kravitch, climb into the room that he is in. Go out the window and to the area where there are CBDC Gaurds on the buildings and enemies behind two blown up police cars. Walk over to the movie theater entrance (Note: You cannot enter it, yet.). Pause your game and highlight the Map option. Press and hold L2+R1+X. Unlimited Ammo[Sent by Evan] To get unlimited ammo press start and go to weapon then press and hold these buttons Right, L2, R2, circle, square, X, keep trying it because it might not work the first time. Hard game mode[Sent by Evan] At the title screen press and hold, Left, L1, R2, SELECT, square, circle, X. Weak Enemies[Sent by Evan] Pause the game then press and hold, Right, R1, L2, X and if you entered it properly you would hear a person laugh. Unlimited Weapons and Ammo's[Sent by Mike] Pause the game, highlight weapons at the same time hold down: L-2 + R-2 + right + square + circle + x this code must be entered at every level after a major briefing.