Instructions
Begin a game in Scenario mode. Finish chapters 1 and 2 to unlock Kakashi, Shikamaru and Sakura. Beat chapters 3 through 6 to unlock Tenten, Guy, Neji and Rock Lee.
Complete Scenario mode in its entirety to unlock several more characters and a series of harder missions called Atatsuki mode. Gaara, Temari, Sasori, Kankuro, Deidara, Itachi and Kisame are now available to you.
Enter Mission mode from the main menu. Select and finish B rank mission 4, Social Training Members, to unlock Sai. Finish all other missions to unlock Kakashi's second form.
Start Akatsuki mode from the main menu. Beat all 10 missions without losing once during your play. If you die when trying to complete a mission, return to the main menu and start again. When you complete all missions, you will unlock Naruto's second single-tail form. If you have also beaten Scenario mode along with every mission, you will unlock Naruto's ninetails form.