Note: This game is also titled Naruto: Gekitou Ninja Taisen!.
Unlock Rock Lee, then successfully complete Single Player mode two times with all characters. Then, highlight Nartuto at the character selection screen and press X (for the orange suit Kyuubi) or Z (for the red suit Kyuubi).
Play the game in Story mode. Use no continues and defeat Zaibuzan. Defeat Rock Lee when he appears to unlock him.
Unlock Kyuubi Naruto, then successfully complete Single Player mode with him. Then, successfully complete Single Player mode with Kakashi. Highlight Kakashi at the character selection screen and press X or Z.
Successfully complete Arcade mode with Zabusa on Difficulty 3. Then, highlight Haku at the character selection screen and press X or Z. When Haku is hit in the face, or is hit and takes a lot of damage, Haku's Mask will fly off his face.
At the character selection screen, highlight a fighter and press Y.
Successfully complete Single Player mode with all default characters to unlock the "Sounds Test" option in the Omake menu.
Finish in first place in Time Attack mode to unlock Attack Power 4.
Finish in first place in Survival mode to unlock Difficulty 4.
Hold A to charge up shurikens/projectiles to throw more of them.
When performing Kakashi's special, hold Y for it to charge and him to attack automatically. The attack will go farther and do more damage.
To win easily press Forward, B(5). Before your opponent gets back up, use it again. If you get hit, press R and use Substitution Jutsu. You will probably have lots of Chakra. Note: You must have a green Chakra level to perform Substitution Jutsu.
With Sakura, after pressing A for shuriken, press A again for another, then A again for a finsher to the combo. Haku can do sort of the same thing, however after pressing A initially you can only press A once more.
One of Sasuke's best combos is B(4), A. The Fire Jutsu causes a lot of damage and if timed correctly, can kill the opponent.
When your opponent uses their super, use your counter. If done correctly, Kakashi will do his own version of your opponent's super.