Play as Rock Lee:
To unlock Rock Lee play the game in Story mode and defeat the Zaibuzan without using any continues.
Play as Kyuubi Naruto:
Highlight Kyuubi Nartuto at the character selection screen and press X or Z once you have unlocked Rock Lee and successfully completed the game in Single Player mode with all the characters.
Play as Sharingen Kakashi:
Highlight Sharingen Kakashi at the character selection screen and press X or Z once you have unlocked and completed in Single Player mode Kyuubi Naruto.
Alternate Costumes:
Highlight a fighter and press Y at the Character Selection screen.
Sound Test:
To unlock the Sound Test option in the Omake menu successfully complete the game with all the default characters in Single Player mode.