Our hero is Dave Lizewski (Aaron Johnson), who wonders why nobody has ever tried to take on the criminal underworld with a cape and cowl, either for justice or for mental health reasons. In between comic stops with his buddies Marty (Clark Duke) and Todd (Evan Peters), and fantasies about the stunning Katie Deauxma (Lyndsy Fonseca), Dave decides to be the first. After ordering a scuba suit and tracking down a pair of persistent bullies in a nearby alley, Dave emerges from his first crime-fighting escapade with metal grafted onto nearly every bone in his body, nerve damage that's messed with his pain sensitivity, and a brand-new name: Kick-Ass.

Unfortunately for Dave, another masked superhero named Big Daddy (Nicolas Cage) and his daughter Hit Girl (Chloë Grace Moretz) are out and about, and their mission is revenge. The target is a powerful gangster named Frank D'Amico (Mark Strong), and when they start swiping his coke, Frank starts hearing stories from his goons about caped crusaders. Frank is furious, and when he sees a TV report on Kick-Ass following one of the break-ins, he turns his murderous gaze on the unsuspecting teenager.

Midway through the movie, Dave takes on three thugs in a parking lot, who question his noble intentions. Dave's response, as ridiculous as it might seem with the mask on and blood pouring down his face, is almost inspiring in its conviction, and for that moment, Kick-Ass genuinely kicks ass. Dave's belief in what he's doing, broken bones and all, is a moment of hero worship that transcends geekery; it's a moment that has helped define Dave as an honorable person. The Spider-Man of the movies learns his lessons through external trauma and poor decision-making, but Dave feels a bond with the Supermans of the world, and it's a great, genuine character revelation.

This conviction is completely sold by Aaron Johnson, who's seriously great when the screenplay has enough for him to chew on. Most of his role is nerd schtick, and he's good at that too, but it doesn't allow him to shine as brightly as Dave's transformation from man to friendly neighborhood superhero. The same goes for Christopher Mintz-Plasse, who plays another would-be superhero named Red Mist. Like Johnson, Mintz-Plasse is fine, but (call me crazy) I thought Role Models offered more room to see a real person rather than further riffs on the awkward nerd, and I'm not sure the movie sells his character arc well enough. Really, it's the supporting cast that stands out. Clark Duke is very funny as Marty, and with this, Hot Tub Time Machine, and Sex Drive, under his belt, he's seriously established himself as a comedically-lethal supporting player, while Mark Strong can add a similar notch to his belt as yet another varied villain. D'Amico is a mixture of crazy and dangerous, and Strong vividly illustrates the man's strengths and weaknesses, sometimes in the same moment.

If you've seen any ads for Kick-Ass, though, you'd probably think that the whole movie was about Chloë Grace Moretz as Hit Girl, whose foul mouth and skill with a bladed weapon are juxatposed with the fact that she's eleven years old. There are definitely awesome scenes in which Hit Girl mows down crowds of would-be killers (particularly a slow-motion hallway scene in the third act, including a lasso/firearm trick that should get a great reaction), but the script and direction do a bit too much "look-at-us-we've-got-a-murderous-preteen-who-swears-like-a-sailor" for my tastes. Moretz may put the "pro" in profanity, but Hit Girl is better when she does rather than says. Cage, meanwhile, flips back and forth between personalities akin to an "aw-shucks" dad from a 1960's TV show, to a bizarre, Shatner-esque syntax when he's in the costume (Cage said in interviews it's meant to be Adam West, but for the life of me, all I could hear was Captain Kirk).

When all of this is taken together, as an action movie and a comedy, Kick-Ass is good, but not great (the friend who attended the screening with me pointed out that the delivery is almost identical to Zombieland, which may have inadvertently stolen this movie's thunder by arriving first). But as a comic book movie, the film does have something special: it manages to get across, in spades, the psychology of superheroism in ways that no other movie has managed. The famous tagline for Superman was "You'll believe a man can fly!" Watching Kick-Ass, not only will you believe that human beings could soar across the skies, but you'll understand why those people, super or not, would be driven, body and soul, to help someone in need.