Level select
Pause the game and press Up, Left, Right, Down, Right, L.

99 lives
Pause the game and press Left, Right, Down, Right, Left, R. -From: factory81kid@yahoo.com

Invincibility
Pause the game and press Right, Up, Right, Left, Right, R. -From: factory81kid@yahoo.com

All powers
Pause the game and press Down, Left, Right, Left, Up, L. -From: factory81kid@yahoo.com

All items
Pause the game and press R, Up, Left, Right, Left, L.

Refill health
Pause the game and press L, Down, Left, Up, Down, R. -From: XXNyCpLayA2kXX@aol.com

Infinite continues
At the continue screen after no lives or continues are remaining, press Up, Down, Right, Left, Start to continue without using a continue.