The superheroes in Kick-Ass don't have super-powers or fantastical technology, but they're not regular people. They're psychopaths, severely damaged and mentally shredded. The same, Kick-Ass suggests, goes for the whole superhero genre and those who love it. Minor spoilers below.
People have tried to "deconstruct" superheroes at the movies many times before — we've had comedies like The Specials and Minute Men, and weird dramas like Sidekick, not to mention last year's self-important Watchmen — but they all treated the genre too kindly.