Get More Plasm:
To get more "Plasm" points from each kill, get in as many consecutive hits as possible. The more consecutive hits you get, the more damage you do and the more plasm you get from each kill... which essentially means more powerups faster!

Restore Health:
Start a game, whether new or a saved game and while playing, press Up(2), Down(2), Left, Right, Left, then hold Back and press Right

Restore time dilation:
Start a new game or load a saved game and while playing, press Up(2), Down(2), Left, Right, Left, then hold Back and press Up.

Remove display:
Start a new game or load a saved one and while playing the game, press Up(2), Down(2), Left, Right, Left, then hold Back and press Y.

Restore time dilation:
Start a new game or load a saved game and while playing, press Up(2), Down(2), Left, Right, Left, then hold Back and press Up.