Here are some cheats and tips for the game The Last Ninja.
Final battle:
Enter 550446503776HC6 as a password.
Fifteen lives:
Enter HHHHHHHHHHH0HHH as a password.
Level Password
2 611111612314901
3 C444444F5041DG4
4 7000008036058C0
5 HCDCD8081086048
6 BG9G9F5FCFD950F