There’s a sequence at the start of Wes Anderson’s Rushmore when the teen protagonist stages an adaptation of Al Pacino thriller Serpico as a school play.  It’s correct in most details, as long as you’re kind enough to overlook the central problem: schoolkids playing adults look kinda dumb when it’s done so straight, and the consequence is you’ve got to wonder whether it’s worth the bother.

There’s a similar dilemma at the heart of Zack Snyder’s adaptation of the Alan Moore and Dave Gibbons graphic novel classic Watchmen.  It’s done pretty well at a purely visual level, but in the process of adapting a story that utilises the devices of a comic more effectively than pretty much any other, it demonstrates precisely why writer Alan Moore claimed the story wouldn’t work on screen, and Terry Gilliam agreed with him.  What you’re left with is like one of the sketches by autistic teenage artists that crop up on slow news days from time to time: convincing in every respect, but lacking the heart of the original.

So, congratulations Zack Snyder: you’ve put the autistic into auteur. It takes a while to realise, that’s all: the opening sequence setting up a world in which masked vigilantes play a part in 20th century history is superbly achieved, if slightly portentuous against a Bob Dylan song and in the slo-mo that characterises much of the film’s action.

The film is heading for 3 hours long, and I swear they could cut it by 20 minutes if they ran it at normal speed.  But then we wouldn’t get to fetishise the visual detail that Snyder has plucked from the comic and put on screen for us to enjoy.  And some of it is, sure enough, mighty impressive — the director is at home with this techy side of filmmaking.  It’s when human beings are involved that it gets tricky for poor Zack, which is perhaps why he’s made his career with two films where the bulk of the cast are interchangeable: zombies (in Dawn of the Dead) and Spartans (300).

There’s an inherent problem with the way that Snyder presents the superheroes: the comic fully intends them to be mortal, fallible, and not a little ridiculous.  But Snyder wants them to inspire the same awe that Batman does — sometimes anyway — when he’s onscreen.  Which misses the point in a major way.  Watchmen’s protagonists are fuck-ups in the original: onscreen they are every bit as lithe and shiny as the characters the story was designed to deconstruct.

Nevertheless, and if only through the law of averages, there are some good performances.  The strongest is unquestionably Rorschach, whose unwavering moral conviction puts him at the centre of the story as he investigates the death of a former teammate.  Jackie Earle Haley plays the role superbly, and there are several scenes in which Rorschach is every bit as unsettling as the comic intends him to be.  He is masked almost permanently, and the simple bandage-plus-Rorschach-inkblots design works very well: this is mask as Greek theatre intended, a way of tapping into unconscious power.  Pity the same can’t be said for some of the other costumes, which err on the side of trying to be cool in a way that they never were in the comics.

The weakest scenes belong to mother and daughter Carla Gugino and Malin Akerman.  Carla is the original Silk Spectre, a cheesecake take on the vigilante there for the launch parties as much as anything, and Malin takes up the mantle later.  The complex dynamics between them, and the twisted history that binds them, sadly come across as a daytime soap opera, which is a shame as I sense Akerman in particular is capable of a strong performance.  Pity that Snyder is less capable of generating one.

Is Watchmen worth seeing?  I’m not sure how comprehensible it is to someone unfamiliar with the source material: what emotional hit it provides is as much from the memories of the page as what happens onscreen.  Let’s hope that next time Alan Moore says his work is unsuited for screen adaptation, someone actually believes him rather than assuming that what’s groundbreaking in one medium can easily translate to another.  It doesn’t often happen the other way round: how many good comic versions of films are there?  But for some reason (ker-ching) studios insist that the journey can work well the other way.  As for the director; Snyderman does whatever a Snyder can, but that sure doesn’t involve making quality versions of stories that are brighter than he is.