Black Belt Cheats

After you do the last hit (a punch) in Wang, imediately hold 1 and 2 buttons simultaneously and press Up and Down alternately until the final screen (a black one that contains a text) disappear. If you did it correctly you would play in a special chapter which you could fight against the 6 bosses, one by one, again.

Push Button 1 at the title screen. Hold the Reset button at the black screen after the red screen, until Riki appears on the screen. Once this happens, release Reset and the game will start, giving you infinite lives.