Secret character:
Quickly press [Up(2), Down(2), Left, Right, Left,
Right, X, Circle] three times after hearing "Suta Ato,
Oshite ne" spoken. A clashing sound will confirm correct code entry. Enter
the character selection screen (not story mode), and press R1.
Play as Shinobu:
Choose a difficulty of two or three stars and finish the game without using
any continues. Fight Shinobu to complete the game. Go to Vs. mode and press R1
or R2 to play as her.