Kick-Ass writer Jane Goldman talks to Ben Child. Warning: this video contains very explicit language guardian.co.uk

Superheroes have always represented something of a challenge for film-makers. It's all very well for comic-book writers to create characters with laser vision and the ability to leap tall buildings at a single bound, but until advances in CGI, it was nigh on impossible to recreate them on the big screen. Even the original Superman always looked a bit like he was lying on his side on the floor of a big blue room, rather than flying through the skies, politely showing Lois Lane the view of Metropolis from up above.

It's no surprise, then, that the current slew of comic-book movies has arrived just at the point when special effects have reached a level of excellence at which it is finally possible to make the fantastical appear real. Spider-Man can swing through the skyscrapers of Manhattan with ease, while the Incredible Hulk is no longer just an enormous bodybuilder covered in green paint. Technology has finally caught up with the dreams and visions of the 20th-century's most famous comic-book writers, and superheroes have become ubiquitous on the big screen.

In the past decade, Fantastic Four, Iron Man, the Hulk, the X-Men, Watchmen and Hellboy have all made their debuts, while Ant-Man, Thor, Captain America and the Avengers are on their way. If the late 1930s and 40s were the golden age of comic books, the past decade and the one to come look set to be the golden age of comic-book movies.

There's just one small problem, and it's one that is at the heart of the creation of Kick-Ass, a comic-book character so postmodern that he makes all those who came before look like relics of a bygone age. The dreams and visions of comic-book readers and cinemagoers in the 1930s – or 50s and 60s in the case of many of Marvel's characters – are not those of today's audiences, no more than the 60s version of James Bond, with his misogyny, preposterous gadgets and cheeky one-liners, is suitable for a spy thriller in the new millennium. Something fresh and new is required.

"The film world is plundering these characters that have been around for an awfully long time," says Jane Goldman, the screenwriter of Kick-Ass, who worked with comic-book creator Mark Millar and director Matthew Vaughan to bring the film to cinemas. "I think it's just the way that the comic-book industry works. Mark was wondering where the next set of heroes for our generation was."

Kick-Ass is defiantly unconventional when it comes to comic-book tropes. He has a normal American name, Dave Lizewski (so normal that it was borrowed from the real-life winner of a competition to christen the character), and real-life teenage problems. He doesn't have a girlfriend, though desperately wants one, and hasn't really got much of a clue about what he wants to do with his life. All he knows is that he loves comic books.

"He's extremely different because he doesn't have any superpowers," says Goldman. "He's an average guy – he's not a cartoon nerd, he's just a regular teenage boy who happens to love comic books and wonders why nobody's ever tried to be a superhero. With that fabulous teenage lack of logic he decides to give it a try, which is obviously an appalling idea in real life."

Rather than triumphantly dispatching his thug opponents during his first street battle, Dave has the living daylights beaten out of him and winds up in hospital, where he spends months recovering having extensive, expensive rehabilitation, which his night shift worker dad can ill-afford. When he finally does make an impact – after saving the victim of a mugging from his attackers – he is caught on phone camera and becomes an instant YouTube sensation.

"I always thought it would be good to do a realistic superhero book," says Millar, a Scot with the cheeriest disposition this side of the highlands, who is chief writer for Marvel. "You always hear the word realism with superheroes but it never really is. Watchmen isn't that realistic – there's a big blue guy with his dick out, you know? It's not like a guy just putting on a costume, going out with no superpowers and trying to make it happen.

"The trouble is that the superhero movies so far – and I don't want to be unfair to them because I think generally they have been good – have been made two generations after they've been created, and in Superman's case three generations after they've been created. So if the technology had existed to make a Fantastic Four movie in 1966 it would have been amazing, because you had Kennedy and the space race and all of that. But now, really, what is the Fantastic Four?

"With Kick-Ass, the book's just out and now the movie's out six weeks later. And I think that's the way things are going to go now, because to go to Marvel's B and C-list characters and try to get movies out them - what's the point of that?"

Certainly the likes of Captain America look pretty hokey in comparison to Hit Girl, a foul-mouthed 11-year-old whom Kick-Ass encounters during his adventures. She's a tiny yet deliberately supercool figure played in the film by Chloe Moretz, who slices up opponents with samurai skills and can wield a glock with finer precision than Dirty Harry or Death Wish's Paul Kersey could ever dream of. There's something Tarantinoesque about putting such a figure in a relatively mainstream movie, and to his credit Vaughan and Goldman have refused to tone down the character described in the comic book as "John Rambo meets Polly Pocket", despite the predictable tabloid ire. She still crashes into our conciousnesses with the immortal line: "Okay, you cunts, let's see what you can do," and the extreme violence superbly illustrated by John Romita Jr in the comic has only been tempered a little for the cinema.

Kick-Ass is a remarkable vision to find its way to the big screen virtually unadulterated. No studio would touch the project when Vaughan hawked it around Hollywood, and the director had to finance the whole thing himself. But then the graphic novel was also a leap of faith: neither Millar nor Romita were paid upfront, and the latter spent two years working for nothing on the artwork, and later as a consultant on the film.

"I was so set on doing mainstream work, but my wife said: do something out of the ordinary, you're so used to doing regular books," says Romita, a buff yet gentle figure who has worked on some of Marvel's most famous comics since the 1970s. "I knew that with the following Mark has and whatever following I have, people would at least pick it up. But I had no idea it would turn into this. There's always someone who's a page ahead of everybody else and sets a precedent. This time it's Mark, and now everybody is going to follow on from this."

Could Kick-Ass really usher in a new era of comic-book movies? Millar and Vaughan are so confident of the success of Kick-Ass that they have already begun plans for the sequel, and the comic-book writer is also in talks to start work on a separate comic book and movie double-header featuring a super-villain as the lead character, something he would not even have considered a few years ago.

"I think you need to be familiar before you can subvert," he says. "Kick-Ass is very knowing towards Sam Raimi's Spider-Man and the other films which came before it. What's quite interesting now is that we've given people a broad education in superheroes and now we can start to play around with it a little bit. I'm trying to create a new wave here and get more radical with it – you certainly couldn't have done a supervillain 10 years ago because people weren't familiar enough with superheroes to turn that on its head and do the story from a supervillain's point of view."

But what of those film-makers trying to bring more antiquated characters to the big screen? What about the torrent of comic-book movies that studios have on their slates? "They're fucked," grins Millar. And suddenly there's a little bit of Hit Girl in him. "It's a weird situation because Mark Webb is redoing Spider-Man now and in Kick-Ass the characters make jokes about the conventions of that character: it's all stuff about somebody's mum getting killed and it is funny. You can't have Peter Parker with his gentle humour in the Spider-man reboot now - it's going to look like Humphrey Bogart or something."