This long-awaited adaptation of Alan Moore and Dave Gibbons's seminal comic-book mini-series is less faithful than totally obsessive - a fanboy's love letter to a complex, adult work that deconstructed the American superhero myth on its original publication in 1986. Lifting whole frames from the source material, director Zack Snyder (300) delivers a dark, violent epic set in an alternative 1980s in which America was victorious in Vietnam, Nixon remains president and masked crime-fighters have been outlawed by legislation. It's here that brutal and obsessive mystery man Rorschach (Jackie Earle Haley) investigates the murder of former "mask" The Comedian (Jeffrey Dean Morgan) and unravels a complex conspiracy involving quantum superman Dr Manhattan (Billy Crudup). Hyper-stylised visuals capture the noir-style seediness of Moore's world brilliantly; less convincing are the latex costumes and ill-judged deviations from the text. Those unfamiliar with the work will probably be completely bewildered, while reaction from fans to this bold but flawed take on one of the genre's sacred cows is likely to be divided.

In a gritty and alternate 1985, the glory days of costumed vigilantes have been brought to a close by a government crackdown. But after one of the masked veterans is brutally murdered, an investigation into the killer is initiated. The reunited heroes set out to prevent their own destruction, but in doing so they uncover a sinister plot that puts all of humanity in grave danger.