99 Credits:
Press Up, Up, Down, Down, Left, Right, Left, Right, Circle, Square and Select at the main menu to get 99 credits.
Unlock Levels and Options:
Complete the game with an A ranking to get an alternative ending and unlock Training mode level 6. Complete the game with a B ranking to unlock Training mode level 5, Theatre and Database modes.
30 Lives:
Use controller 2 and enter Up, Up, Down, Down, L1, R1, L2, R2, L3 and R3 at the main menu. This will unlock 30 lives.