Danger Girl cheats, and Codes for PSX.
Unlock Levels and Cheats
From the Main Menu, press L1, R2, L2, R1, Circle, Square, Triangle (x2), then hold L1 + L2 + R1 + R2. This will unlock all the levels, and will also unlock the Cheats menu.
Some cheats are unlocked by finding special icons in different levels.