Director Matthew Vaughn had to finance Kick-Ass on his own, because the studios wanted to avoid a violent, profane R-rated comic-book movie with teenagers (and one pre-teen) killing bad guys. But he’s beaten the studios at their own game, making an entertaining, fulfilling and all-around better superhero movie. The story about everyday people becoming costumed heroes is punctuated by strong performances and unforgettable action sequences, each with its own energy and look. The star attraction is clearly Hit-Girl (Chloë Grace Moretz), a butterfly-knife-wielding, foul-mouthed small fry in a purple wig.