A few months back there were plenty of doubts about Iron Man. The comic book character, a rich industrialist who designed a supersuit to fight crime, is not one of Marvel’s most defining characters. And many doubted the talents of director Jon Favreau, who has only directed kid-oriented fluff such as Elf and Zathura, and lead actor Robert Downey Jnr, who has had more relapses than hit movies. Yet slowly but surely, the film began to pick up momentum, and this weekend, its first, has seen it earning $200 million worldwide. Reviews have been kind, so is Iron Man a worthy first blockbuster of 2008?

The film traces the origins of Iron Man. Tony Stark, designer of advanced weapons of mass destruction, is kidnapped in Afghanistan by terrorists, and forced to build weapons for them. Instead, he invents a clunky suit to escape, after a fellow prisoner, Yinsen, manages to show him the consequences of his missile designs. After escaping, Stark decides to work for peace instead, but faces resistance by his business partner Obadiah Stane (Jeff Bridges), who has plans to steal Downey’s iron man design.

There are two reasons why Iron Man works as a film. The first is the sheer entertainment value. There’s plenty of wit to keep you amused between plot points. If it’s not Stark’s dry wit, then it’s the physical humour. For example, rather than bore us with a montage of tests Stark makes to the suit (we already get this earlier on as Stark plans his escape attempt), we’re treated to a running gag involving one of Stark’s robotic sidekicks and a fire extinguisher. Plus, the pacing of the film is rather quick. Director Jon Favreau is smart enough to recognise that the love interest isn’t that interesting and doesn’t linger on it, instead remaining flirty and suggestive.

And then there’s the story. In the last few years we’ve seen a slew of superheroes and blockbusters that are quite insular. They’re about tortured souls who have to make choices, before taking on the big badguy while avoiding their identity being revealed, etc. But with Iron Man the story has a political dimension. It’s pretty obvious, a liberal take on capitalist war-profiteering, but for a popcorn flick aimed at adolescents, it’s not a bad attempt.

I’ve never been a huge fan of Robert Downey Jnr, he always seemed like a lazy actor, even when he’s good in films like Zodiac. But he has settled nicely into Tony Stark’s shoes. Maybe its because both were alcoholics, but Downey adds a certain shabbiness of character that makes Stark more real. Gwyneth Paltrow, who plays his PA, makes a welcome return to mainstream cinema, and although I felt the Pepper Pots should have been played by a younger actress, she does glide along gracefully. And Jeff Bridges does well as being the charming business associate who is cloaking a heart of darkness, but doesn’t get to shine in his villainy.

But that’s not to say the film is without flaws. The film’s big finale feels a little insignificant, almost like the final obstacle in perfecting his suit, rather than a fully fledged nemesis. And Stark is left with next to no time to have any emotional reaction to Stane’s betrayal.

There’s also the idea of Iron Man himself. While the context of his story allows for some gentle political commentary, there’s something slightly stale about him. Maybe its because we’ve already seen enough heroes with plenty of money (Batman) or scientific know-how (Fantastic Four), battling their inner demons (you name it…) to do the right thing. It’s not Favreau’s, Downey Jnr’s, or even the scriptwriter’s fault, rather we may be suffering from superhero saturation.

Yet, despite that, I enjoyed watching Iron Man. It was light and exciting enough, with a dash of political criticism, making it a pleasing start to the summer. A sequel has already been commissioned, and I for one will be eager to see it.