You get your first star by reaching lv. 100. Once you get a star, you go back to level 1 and start over. Your second star comes at 110, then 120, 130, 140 and your sixth star at 150. Once your each your sixth star, I'm not sure if you go back to level 1, but you will be able to level as high as you want afterwords. In short: Don't worry about stars, they take forever to get.
 "A Knight's Story"){kind=icon}
 "Sonny"){kind=icon}
 "Tactical Assassin 2"){kind=icon}