During the game, pause and hold either L or R. Then press the following buttons for the specified cheat:

Down, B, Up, Left, Up, Left - Refill health

Right, B, Down, Up, Down, Up - Maximum health

Right, Right, Left, Y, Right, Down - Refill magic

Y, Right, Down, Right, Up, Y, Left - Maximum magic

Down, B, B, Left, Right, Y, Up - Pass through barriers

Y, Down, X, Right, Up, Down - Wall climbing