Unlock All Characters In Versus Mode:
     At  the  Press  Start Screen, press Up, Down, Down, Right, Right,
Right, Left, Left, Left, Left, then hold Circle and press Start

Unlock Trial Mode:
     At  the  Press  Start Screen, press Up, Down, Down, Right, Right,
Right, Left, Left, Left, Left, then hold Triangle and press Start

Unlock Sudden Death Mode:
     At  the  Press  Start Screen, press L1, R2, L2, R2, L2, Triangle,
Circle, Triangle, Circle, then hold L1 and press Start