Samurai Shodown 3

Play as Zankuro:
Go the the Versus mode and highlight Haohmaru with both controllers, then press LEFT(x2), DOWN, RIGHT(x2), UP, RIGHT, DOWN, RIGHT(x2), UP, LEFT(x2), then press X + Circle + Start.

Unlock VS. Mode:
At the title screen, hold L1 + R2, then press RIGHT + Square.

All Skills in VS. Mode:
Pause the game in VS mode, then hold R1 and press LEFT(x2), RIGHT(x2), L1(x2), L2(x2), L1, RIGHT, LEFT.

 