Cheat Code:
After you press start, before you select new game, input the following code. (you will hear a confirmation sound if you do it correctly)
Enable Dark version of the Revived Hunter:
L1 x 3, R2 x 1.
Enable Ultimate Armour for X:
Left x 3, Right x 1.
Cooperative Mode:
Highlight Continue, hold Select and press R2 (21), Left, Down, L1, L1, L2, R2, Start.
Use Dark Revived Hunter in Cooperative Mode:
R2 (5), L1 (8), Left, Down, Left, Up, Left, Right, Right, Right, Start.
Hard Mode:
Highlight New Game and press Left, Left, Right, Right, Left, Up, Left, Down, Right, Start.
Nightmare Megaman Zero or X:
Highlight New Game and press R2, L1, L2, R1, Left, Down, Right, UP, UP, Left, Down, Select, Start.