At the title screen, choose "Options". In the Options menu, select "Shuriken"
for Sound Effects, "Shinobi" for Music, and "Shuriken Hits" for Voice. Now
move back Up to the "Shuriken" option and set them to 00. Stay on this
option and wait until it turns into an infinity symbol.
At the title screen, choose "Options". In the Options menu, move Down to
the "S.E." command and use the B button to play these songs in order: "He
Runs," "Japonesque," "Shinobi Walk," "Sakura," "Getufu." Exit the Options
screen and Start your game. You are now immune to all damage!
