On the Title Screen, press Up, Down, Right, Left, X (3x).

Unlock Score Cheats

Pause the game and press Right, Right, Left, Left on the right controller. 

Unlock Full Health

Pause the game and press Up, Down, Right, Left, Square (3x). 

Unlock All Characters

While at the Title Screen, press L1, R2, L2, R1, Right, Left, L3, R3. 

Unlock More Items

While at the Items Screen, press R2 + L2, then press Square (3x), Up Left, Down, Right. 

Unlock All Items

While at the Items Screen, press R1 + L1, then press Up, Square, Square, Left, Square, Square, Down, Square, Square, Right, Square, Square. 

Unlock All Missions

While at the Mission Select Screen, press L1, R1, L2, R2, Right, Square, L3, R3. 

Unlock Bonus Stage

While at the Title Screen, press L1, Up, R1, Down, L2, Right, R2, Left.