Cheat Codes
Complete and save the game on any difficulty setting. Start a new game from the saved game file, and wait until the starting sequence ends. After Rain leaves, you should see a small control pad on the left-hand wall immediately after the screen switches. Walk up to it and the Use option should appear. Press the Triangle. Enter one of the following codes to activate the cheat function.

Enter these at the small control pad:

All weapons - 11692
Infinite ammunition - 61166
Big head mode - 10397

Art Gallery
At the main menu of disc 1, where it says PRESS START, press left, right, up(2), down, circle. If entered correctly you should here a sound. Then go to options, extras and "ART GALLERY" will be selectable. For disc 2 press, up(2), R1(3), square. For disc 3 press, L1, R2, L1, R2, L1, square at the main menu.

Weapon that have impact
List - Effect has impact on

Shotgun, assault rifle - Humans
GL's, shotgun - Creatures/monsters
EMP, then shotgun - Fixers
EMP only! - Military Mechs