Casper cheats, and Codes for PSX. Also see Gameshark Codes for more Casper cheat codes.
Fly over Walls
Move Casper to the upper left corner of any game location. Hold Up/Left + L1 + R1 + Start; the game will pause. While continuing to hold R1 + Start, release Up/Left + L1, and press Down/Right + Triangle. The game will now resume in free movement mode. Now when you want to fly over any wall, press R1, and then move over the wall. Press L1 if you want to return the game to normal.