Naruto: Ultimate Ninja Heroes was just a warm up. This summer Namco Bandai is localizing the actual game Japan got back in 2006 as Naruto: Ultimate Ninja Heroes 2: The Phantom Fortress. The main difference between this and the US/Europe only Naruto: Ultimate Ninja Heroes is a single player storyline where players push through 100+ floors of an illusion filled Phantom Fortress. Scrolls are used build a path to the staircase and they contain tasks like one on one fights, trivia questions from Iruka and mini games like the tree running game from Naruto: Ultimate Ninja 2.
The good news is Namco Bandai is slightly improving the game for North America. Naruto: Ultimate Ninja Heroes 2: The Phantom Fortress has the game sharing function introduced in the previous PSP release and dual language support (i.e. Japanese and English voices).