Full Options Plus
Start the game, then pause it by pressing Start. Now press Up, Up, Down, Down, Left, Right, Left, Right, B, A and Start.

Full Speed and Shields
Start the game, then pause it by pressing Start. Now, press B 5 Times, then A 5 Times. This will work once per game.

Full Power Down
Start the game, then pause it by pressing Start. Now press the A Button, then Left four times, then repeat the sequence four more times. Use this code only if you want a real challenge; it will take away all your ship's accessories!

No Power Ups
Start the game, then pause it by pressing Start. Press Up, Select, Down, Select, Left, Select, Right, and Select, then repeat this sequence twice more. Use this code only for added challenge; it prevents you from powering up your ship!

Bonus levels
Level 2
Destroy the volcano towards the top after the ceiling drops and rises. Fly through the hole where the volcano was located.
Level 4
Destroy the second Re-Bone blocking the narrow passage near the end of the level. Fly to the bottom of the passage to reach the wall behind your ship.

Expert mode
Pause game play and press Up, Select, Down, Select, Left, Select, Right, Select(3). Collecting power-ups will have no effect on your ship.