To unlock most characters you must select "single player mode" and complete single player (10 battles) with all the starting caracters (Naruto, Sasuke, Sakura, Lee, Jiriah, Kakashi and Neiji). And you must also finish "Mission mode" once in Chunin (you don't have to finish all of the levels of difficulty) Note: there are actualy 23 missions in "mission mode" to unlock them you must fight in single player in "single player mode" with the starting characters. You can also do time attack to unlock the juke box and the voices of the characters.