God mode:
Press Up, Down, Left, Right, L, R, Left, Right, Start during game play.

Additional lives:
Press A, B, X, Y, L, R, Up, Down, Left, Right during game play. 

Additional credits:
Press A, B, Left, A, B, Right, B, A, Down, R during game play. 

Level select:
Press Up, Down, Up, Down, Up, Down, Left, Right(2), Y during game play. 

Level skip:
Press Y(2), X(2), L, R, Down(2), Up(2) during game play. 

Grenades:
Press Down(5), Up(4), R during game play. 

Instant victory:
Press L, R, L, R, Left, Right, Left, Right, Y, X during game play. 

Shields:
Press Up, Down, Left, Right, X, Up, Down, Left, Right, Y during game play. 

First person view:
Press L, Left, R, Right, X(2), Down(2), R, L during game play. 

View ending sequence:
Press L, R, L, R, Left, Right, Left, Right, Y, X during game play.