All Weapons:
Pause the game and press Up, Up, Down, Down, L, R, L, R, B, then A. When you unpause the game you should have full power-ups. This code only works a few times a game. also...

Self-destruct:
Pause the game and press Up, Up, Down, Down, Left, Right, Left, Right, B, A. When you unpause the game you'll have full power-ups for a few short seconds then you'll self-destruct.

Thanks to Revolution reader Jim Brodhagen II!