Open the 'Stage Practice' Mode
Open the 'Stage Practice' Mode on the main Screen, where you can practice any level that doesn't have a boss.
Stage Practice Mode - Hold down the A, B and C buttons, and press START at the Opening Screen.
When you have the Weapons Upgrade item, walk and you'll notice the shinobi holding a light on his wrist. This light is the Mystic Shield. It will protect you against small projectiles like ninja stars and bullets, but not against bigger ones like the grenades the soldiers throw.
Go to the Options Screen, move the pointer up to Shurikins and set them to 00, wait about 30 seconds (without moving the pointer). You will here a sound and the ''00'' should change to an infinite symbol. Start the game and you will have unlimited Shurikins.
One the second stage of level four,fire at the base of the first conveyer belt.A special Musashi symbol will appear.Hop onto the conveyor belt and let it carry you to the end.You lose a life but you gain 2.Keep doing this until you have as many lives as you want/need.
30,000 Bonus Points
If you want to earn 30,000 bonus points, make sure you end a level with eleven times more shurikens than the number of lives you have left.
There are 9 Bronze Trophies, 2 Silver Trophies, and 1 Gold Trophy.
A Clash With Evil (Silver) - Defeat the Round 1 boss without using the 8-way Shuriken Attack.
Beautiful Assassin (Bronze) - The dancing lady in Chinatown must not be defeated!
Behold! Emblem of Blue! (Bronze) - Appreciate the SEGA logo.
Brawn Over Ninjutsu (Silver) - Finish 6-1 without using any Ninjutsu.
For Naoko. For peace. Shinobi forever! (Gold) - Rescue Naoko without using a continue.
Impenetrable Wall (Bronze) - Guard 10 attacks with your cross-guard.
Miraculous Ninja Arts (Bronze) - Use all four types of Ninjutsu in one game.
Shinobi Has Fallen (Bronze) - How was that dive into the waterfall?
Shinobi Watches (Bronze) - Stand atop the brick pillar in 3-1. Ninja style!
Shuriken Rain (Bronze) - Use 300 Shuriken.
Shuriken Starburst (Bronze) - Demonstrate Joe Musashi's 8-way Shuriken Attack.
The Traps of Neo Zeed (Bronze) - Trigger 10 bombs.