With this cheat the graphics will become blocky but the game's frame rate will improve.
When the 'Press Start' message appears at the title screen, press:
Left, Left, Right, Right, Down, Down, A
The game title will change to confirm.

With this cheat all bonuses and practice levels will be unlocked.
When the 'Press Start' message appears at the title screen, press:
Down, Down, Up, Up, Left, Right, Left, Right, B, A