Zack Snyder's Watchmen is flawed. Having watched some footage presented by the director months ago - and having read Alan Moore's graphic novel three or four times until I finally understood all its diverse layers and interconnections - I was hugely looking forward to this superhero film to end all superhero films. For the unversed, Moore envisaged a 1980s world where Nixon remained in power and the Cold War prepared to heat up. A group of non-super "costumed adventurers", inspired by an earlier 1940s group, had been first rendered redundant by the arrival of the genuinely superhuman Dr Manhattan (a scientist given god-like powers in a nuclear accident) and then outlawed as vigilantes, or co-opted into service, by the government. Snyder's film looks stunning, and at times even improves on Dave Gibbons's now rather-dated illustrations of Moore's original (particularly the costume of the hero-turned-plutocrat Ozymandias). But there's just too much in Watchmen. At nearly three hours long, the film feels laborious and plot-heavy, yet some of the characters lack crucial back-stories. It's also soft-soaps the vitally important issue that all of them bar Manhattan are just physically gifted (and often rich) individuals, and in no way super-powered. That said, the art direction (particularly the 1980s period detail) is peerless and there are some thrilling sequences. There are bone-crunching fight scenes and the central romance comes with a dose of erectile dysfunction. It's good to see a film deal with the childhood fantasy of superheroes in an adult way, going further into the characters' dark psychology even than Christopher Nolan's Batman Dark Knight movies. But it turns out that when critics called Watchmen "unfilmable" they may have been half right. I wonder what those coming to it fresh will make of it. Let me know, won't you.