Overall a good movie with good pacing.
This film will never appeal to males who watch superhero movies just to gain vicarious pleasure from fantasizing that they are muscular men with great power. The main character, Kick-Ass, is a skinny nerd with no super powers or even martial arts training, and he gets upstaged by a little girl. He also gets stabbed in the gut and run over by a car while trying to be a costumed hero.
This is a satirical superhero story that really draws its inspiration from the ridiculous idea that someone could be a costume-wearing vigilante without any actual super powers and from the preposterous idea that Batman would bring a child (Robin) into the deadly and dangerous world of vigilantism. While Chris Nolan took the idea of a man with no super powers in a silly costume playing vigilante and made some deadly serious, utterly humorless movies out of that idea, this movie plays up the sheer absurdity of it all and revels in not taking it all seriously.