It tells the story of an ordinary teenager, Dave Lizewski (Aaron Johnson), who sets out to become a real-life superhero, calling himself "Kick-Ass".

Dave gets caught up in a bigger fight when he meets Big Daddy (Nicolas Cage), a former cop who, in his quest to bring down the crime boss Frank D'Amico (Mark Strong) and his son Red Mist (Christopher Mintz-Plasse), has trained his eleven-year-old daughter (Chloë Grace Moretz) to be the ruthless vigilante Hit-Girl.

A sequel, written and directed by Jeff Wadlow and produced by Vaughn, was released in August 2013, with Johnson, Mintz-Plasse, and Moretz reprising their roles.

Before they can kill him, two costumed vigilantes, Hit-Girl and her father, Big Daddy, intervene, easily slaughter the thugs and leave with their money.

Frank's son Chris suggests a different approach and poses himself as a new vigilante named "Red Mist" and befriends Kick-Ass.

Series-creator Millar, a native of Scotland, asked Scottish television children's-show host Glen Michael to make a cameo appearance[9] although his role was cut from the film.

[11] WCBS-TV news reporters Maurice DuBois, Dana Tyler, and Lou Young make cameo appearances along with Marvel Comics creator Stan Lee.

[22] Kenneth Turan of the Los Angeles Times said "the romance provides an appealing backdrop that the more unnerving aspects of the film play out against.

"[23] Other changes included having Red Mist be known to be a secret antagonist from the start, as well as making him less outright villainous, and D'Amico's mob initially thinking Kick-Ass is the one slaughtering their men.

In the original comic-book, Big Daddy is characterised not as an ex-cop, but as a former accountant who had been motivated to fight crime by a desire to escape from his life and by his love of comic books.

[25] The climax to the film differs significantly from the comics, with the use of the jetpack and rocket launcher: Millar called this "necessary" as "we're building up so much stuff that we needed some Luke Skywalker blowing up the Death Star moment".

[24] Comic writer Stephen Grant argued that the film "cheated" on its premise of a "real life" superhero by having these increasingly fantastic events and that this is "why it works.

That's where much of the humor comes from ... when the film finally makes the notion [the fantasy] explicit we're already so deep into the magician's act that our instinct is to play along".

Australian Family Association spokesman John Morrissey said that "the language [was] offensive and the values inappropriate; without the saving grace of the bloodless victory of traditional superheroes".

[3][43] Director Matthew Vaughn felt the 15 certificate was about right and expressed some surprise at the film having received a "PG rating [sic]" in France.

On Sunday, 2 May 2010, it fell down behind A Nightmare on Elm Street, How To Train Your Dragon, Furry Vengeance, The Back-Up Plan, Date Night, Clash of the Titans and The Losers.

These numbers for Kick-Ass's debut weekend gross included non-weekend earnings, as the film was previewed during the Thursday night prior to its release.

The site's critics consensus reads: "Not for the faint of heart, Kick-Ass takes the comic adaptation genre to new levels of visual style, bloody violence, and gleeful profanity.

"[46] Metacritic assigned the film a weighted average score of 66 out of 100, based on 38 mainstream critics, indicating "generally favorable reviews".

[49] Peter Bradshaw gave the film 5/5 stars and called it an "explosion in a bad taste factory" and a "thoroughly outrageous, jaw-droppingly violent and very funny riff on the quasi-porn world of comic books; except that there is absolutely no 'quasi' about it.

"[50] Philip French, writing for The Observer, called the film "relentlessly violent" with "the foulest-mouthed child ever to appear on screen, [who makes] Louis Malle's Zazie sound like Cosette" and one "extremely knowing in its appeal to connoisseurs of comic strips and video games.

"[13] David Cox wrote an article published in The Guardian, saying that the film "kicks the c-word into the mainstream [...] has inadvertently dispatched our last big expletive.

"[51] Chris Hewitt of Empire magazine gave the film 5/5 and declared it, "A ridiculously entertaining, perfectly paced, ultra-violent cinematic rush that kicks the places other movies struggle to reach.

Peter Howell of the Toronto Star gave Kick-Ass a top rating, writing that the production "succeeds as a violent fantasy about our perilous and fretful times, where regular citizens feel compelled to take action against a social order rotting from within.

"[54] Manohla Dargis from The New York Times wrote, "Fast, periodically spit-funny and often grotesquely violent, the film at once embraces and satirizes contemporary action-film clichés with Tarantino-esque self-regard.

"When kids in the age range of this movie's home video audience are shooting one another every day in America, that kind of stops being funny."

[57] Tim Robey of The Daily Telegraph did not like the film either, rating it 1/5 and stating, "Matthew Vaughn's Kick Ass is hollow, glazed, and not quite there".

[58] Karina Longworth writing for The Village Voice, was not impressed with the film's intended satire and themes: "Never as shocking as it thinks it is, as funny as it should be, or as engaged in cultural critique as it could be, Kick-Ass is half-assed.

[72] Selling 1.4 million units within its first week, one-third of these in Blu-ray format, Kick-Ass debuted at number one on the DVD sales chart.

[81] Aaron Johnson and Chloë Grace Moretz reprise their roles as Kick-Ass and Hit-Girl, respectively,[82] and Christopher Mintz-Plasse returns as the main villain, going by the name of "the Motherfucker".