Centipede Codes -

Cheat mode:
Press Start to pause game play in adventure mode. Press L1(2), L2, L1, then press Start to resume the game. Press Start to pause game play again. Press Right for an extra life. Note: An odd number of lives will result in invincibility. A sound will confirm correct code entry.

Level select:
Select "Adventure" from the main menu. Press R1(2), R2, R1 when the level selection screen appears to unlock all of them.