On the character select screen, highlight a character and press Y.
Special Attacks
To use a character's special attack, press the X button when your character's chakra is full. These attacks are powerful, and if used at the right time, can defeat your opponent. To name a few, there is Kakashi's Chidori (Lightning Blade), Naruto's Clone Barrage, Zabuza's Silent Killing Technique, and Lee's Forward Lotus. Or if you're in a tight situation, you can just press the L or R button to use the Replacement Jutsu.
Unlock 9 tailed fox Naruto
To unlock 9 tailed fox naruto beat 1 player mode with every characher 2 times after you get Rock Lee.
Unlock Extra Characters
Rock Lee - Beat Zaibuzan in story mode without using continues, and then beat Rock Lee when he appears.
Kyuubi Naruto - Unlock Rock Lee, and then beat the game with all characters. Now highlight Nartuto on the character select screen and press X or Z.
Sharingen Kakashi - Beat the game with Kyuubi Naruto, and then beat the game with Kakashi. Now highlight Kakashi on the character select screen and press X or Z.
Unlock Hinata
Clear story mode using Sakura. Find this fighter by highlighting Rock Lee and pressing X.