Although one of the movie's messages is that you don't need a costume to be a hero -- all you need is to be brave -- any positive take-away is secondary to the extremely violent and vulgar content. A sequence set in a high school is riddled with sex, as if to say that teen girls must be sexy and sex-savvy to succeed in the world. (Although this could also be a parody of the same idea; it's unclear.)
The frequent, pervasive violence is of the over-the-top, fantasy, comic-book fighting variety, but it gets pretty brutal (with loud punching, pummeling, and falling) and does include gore -- such as spurting blood from heads, stomachs, and feet. Minor characters are brutally run over and destroyed by speeding cars. Characters are stabbed to death with pool cues and bits of broken glass, as well as shot and killed and decapitated. A character is fried inside a tanning booth. A character is devoured by a shark, with clouds of blood in the water. A man is strangled, and a gory photograph of the body is shown. Women are beaten up. Someone's testicles are chewed by a dog. Teen girls are shown violently vomiting and with diarrhea.
Hit Girl, now 15, becomes interested in sex for the first time. Watching a boy band video with three other girls, the movie hints that she becomes aroused for the first time (though she doesn't seem to know what just happened). She has the same reaction when she sees the shirtless (now ripped) Kick-Ass. Two topless women are shown in one scene and are said to be prostitutes. Some references to/suggested masturbation. Kick-Ass kisses and has sex with a girl superhero in a bathroom stall; feet and the tops of heads are all that's visible. Female characters wear revealing costumes, and "The Motherf----r" wears an S&M-style costume. Auditioning for the cheer squad, a teen girl does a sexy "pole dance"-type routine. Sexual innuendo and sexual humor are very strong throughout.
Language is extremely strong, with heavy sexual innuendo. Characters are actually named "The Motherf----r," and "Night Bitch." Words used include (but aren't limited to) "f--k," "s--t," "c--t," "c--k," "c--ksucker," "p---y," "a--hole," "gash," "d--k," "balls," "bitch," "t-ts," "prick," "hell," "damn," "f----t," "penis," "rim job," "knob," "douche," "goddamn," "Jesus Christ," "oh my God," and, of course, "ass." Also plenty of belittling insults, such as "loser" and "nerd."
In one scene set in a convenience store, The Motherf----r shoots up several refrigerators full of Pepsi cans, with several close-ups of exploding cans. Mention of Mountain Dew. The movie is part of a popular comic book franchise.
Drinking, Drugs & Smoking
A character's mother is seen pouring some vodka into a pitcher, and that's about it. No other drinking, smoking, or drugs -- though Hit Girl does take an injection of adrenaline during the final fight.