Unlock Dan:
At the character select screen, select the question mark. Hold L2 and press Triangle, Square, X, Circle, Triangle.
Unlock Bison:
At the character select screen, select the question mark. Hold L2 and press Left, Left, Down, Down, Left, Down, Down, (Square & Triangle.
Unlock Akuma:
At the character select screen, select the question mark. Hold L2 and press Left, Left, Left, Down, Down, Down (Square & Triangle) or (Circle & X).
