Deadly Arts (N64)

Fight as Gouriki:
Press Up, Up, Down, Down, Left, Right, Left, Right, B, A at the title screen.

Fight as Reiji:
Press A, B, Right, Left, Right, Left, Down, Down, Up, Up at the title screen.

Alternate costumes:
Hold L and press Left or Right at the character selection screen. The character portrait will change colors to confirm correct code entry. Then, select a character while L is still held.

Special stage:
Break down all ten buildings in a single stage. Return to the stage selection screen and press Start.