Well, Kick-Ass was also marketed as a superhero comedy, and superhero comedies don't have the best track record (Mystery Men being an example, which opened to $10 million when it debuted... Hancock being the exception because it was a Will Smith movie). The advertisements, that weren't red-band trailers, gave the film an admittedly cutesy Spy Kids vibe that honestly wasn't indicative of what the film was at all about.
Industry analysts and studio executives were hoping for Kick-Ass to mirror the success of Zombieland, which was a surprise success because normally horror comedies aren't that successful. Kick-Ass had a lot of hype going for it, and people were expecting it to do big numbers based on the huge hype, but Internet hype has not always yielded the best results (I'm looking at you, Snakes on a Plane). However, Kick-Ass actually mirrors the success of 2004's The Punisher, another R-rated superhero film with a star (John Travolta in place of Nicholas Cage) and a strong adherence to violence and action. Both films have made similar money, but the obvious difference is that Kick-Ass is actually leaps and bounds better than The Punisher and has a satirical edge that Punisher obviously lacked.
Bottomline, Kick-Ass is a moderate success. The film was financed by investors, having been made outside of the studio system, and the estimated production budget was around $30 million. Lionsgate bought the film for $45 million, which not only reimbursed the investors, gave them a return on their investment, it also put some money back into Matthew Vaughn's wallet, who also contributed financially to the budget. So at the end of the day, Kick-Ass already earned back its budget before it was even released, and the film has earned almost $70 million worldwide. So the only party that might not make a profit is Lionsgate, which is immaterial since if Vaughn makes Kick-Ass 2 (providing he does) outside of the studio system like he did with the first film, he already has a successful formula to gain money again, but the real trick might be getting distribution. However, Kick-Ass should be moderately successful for Lionsgate, with the reciepts surely at the very least allowing them to earn back their costs for marketing. They might not turn a profit, though, so they could be leery about purchasing the distribution rights for a sequel, but there are other studios out there that could be just as willing.
What does this mean for comic-book movies? If anything, R-rated comic-book movies haven't been proven success stories (both Punisher films, The Losers, Watchmen) so studios might be more leery to willingly distribute or finance comic-book movies that aren't PG-13. It is possible the PG-13 rating limited the box office audience of Kick-Ass. I don't think it'll negatively impact the comic-book subgenre as a whole, though. We'll still be seeing more Batman and Spider-Man movies so long as they're successful.
