Master code (Unlock all bonuses):
Hold L1 + L2 + R1 + R2 + R3 (Depressed + Up) + L3 (Depressed + Down) at the main menu. A sound will confirm correct code entry. All bonuses will now be unlocked.

Big Head mode:
Press Start to pause game play, then hold L1 + L2 + R1 + R2 + R3 (Depressed + Right) + L3 (Depressed + Left). A sound will confirm correct code entry.