(NBC) - The hero of "Kick-Ass" is a 17-year-old high school kid named Dave Lizewski, played by Aaron Johnson, who decides to put on a green jumpsuit and become a phantom crime-fighter.
Has he taken leave of his senses?
Dave, who looks like Harry Potter crossed with the young Steven Spielberg, knows he has no special abilities or physical flair.
All he's got going for him, really, is the desire to be a superhero.
It's as if he thought that the sheer power of suggestion could fool the bad guys, and himself along with them.
Named for its hero, "Kick-Ass" is an enjoyably supercharged and ultraviolent teen comic-book fantasy that might be described, in spirit, at least, as reality-based.
Dave quickly learns that fighting evil is no picnic.
The movie never makes it too easy for him, but it doesn't mock him, either.
Adapting the Mark Millar comic book, director Matthew Vaughn stages the film as a vibrant pop patchwork of kamikaze comic-book wish fullfilment.
Playing a mobster's son who becomes a superhero himself, the sports-car-driving Red Mist, Christopher Mintz-Plasse proves great at playing the comedy of aggression off against his spindly, mouth-breathing boyishness.
Just when it looks as if Dave's awkward valor is doing to get him killed, along comes an even unlikelier masked do-gooder: Hit Girl, a pint-size, purple-haired martial-arts demon played by Chloe Grace Moretz.
The joke is that when she turns villains into cannon fodder, it's really no more preposterous than, say, Bruce Willis doing the same thing.
Yet is it a problem that "Kick-Ass" is by far the most graphically violent film ever to feature kids as heroes?
Parents should consider themselves warned, though personally, I just wish the movie had ended up a bit less of an over-the-top action ride.
It didn't need this much slam-bang when it had us at real-life superheroics.