Invincibility: Choose the "S.E." selection on the options
menu. Press B to play the "He Runs", "Japonesque",
"Shinobi Walk", "Sakura", and "Getufu"
songs (in that order).
Six button controller configuration: Insert a six button controller into port one and a
standard controller into port two. Highlight the "Options"
selection at the main menu then hold Mode on controller
one and hold Up + C on controller two. With those
buttons are held, press Start on controller one. The "Options"
menu will appear, with the word "Option" instead of
"Options" to confirm correct code entry. You now can
press A to block button, B to perform a melee attack,
C to jump, X to use Ninjitsu magic, and Y
or Z to throw shurikens. This mode also allows you to use
a melee move at any time.
Unlimited weapons: Set the "Shurikens" selection on the options
menu to 0. Set the "Sounds" option to "Shuriken".
Highlight the "Shurikens" option again and the 0 will
change into the symbol for infinity.
Bonus points: Complete a level without throwing any shurikens to
receive a 30,000 point bonus.