Debug Code To Unlock Hidden Levels:
While playing hold R2, and press UP, CIRCLE, RIGHT, UP, DOWN. A confirming sound should be heard if done correctly. Press select to see debug options.
Pause the game and hold down L2. With L2 held down, press DOWN, UP, LEFT, LEFT, TRIANGLE, RIGHT, and DOWN.
Hearing Gex Speak
Pause the game and hold L2.With L2 held press DOWN, RIGHT, LEFT, CIRCLE, UP, RIGHT. Press select to hear Gex's phrases.