Here are some cheats and tips for the game Ape Escape.
Collect more explosive bullets:
Pause game play and press R2, Down, L2, Up, Right, Down, Right, Left to
collect up to 99 explosive bullets.
Rear-view in ski mini-game:
Press L1 + R1 to get a rear-view mirror during the ski mini-game.
Secret tunnel in Dark Ruins:
Locate the stop sign in the second stage of the Dark Ruins level. Push it
out of the way to find a secret tunnel.