Antichrist, Lars von Trier, 104 mins, (18)

Two months ago, when it premiered in Cannes, Lars von Trier's Antichrist was just a film; now it's a scandal, supposedly (its distributor claims) "one of the most controversial films since A Clockwork Orange". One reason for the fuss is that Antichrist is sexually explicit and extremely violent. But another reason is that, by and large, critics in Cannes felt the film was tosh; many of us duly winced at the brutality, but also laughed at the dafter moments. I mean – a talking fox? What can you say but, "Boom boom!"

Two months on, Antichrist is being acclaimed by some as an audacious masterpiece that the Cannes reviewers were too squeamish and conservative to understand. Now, since no critic wants to look out of touch, there's always the temptation to defend yourself by adopting the Trendy Vicar position: to declare, "I'm certainly no fuddy-duddy, and if young people need to express their sexual anguish by performing impromptu auto-clitoridectomies, then good for them, say I!" So let me just clarify: Antichrist didn't leave me outraged, just unimpressed. Let me also say that, on a second viewing, my first impression stands: I still think it's an ill-conceived, clanking dud.

Charlotte Gainsbourg and Willem Dafoe play a couple whose young son dies in an accident, while they are engaged in graphic slow-motion sex. As bottles and toothbrushes go flying, so does the hapless child. Loss drives the mother into profound grief; the father, a psychotherapist, never reveals his own feelings about the tragedy, but decides to take on his wife as a patient, in defiance of clinical (and marital) common sense. Persuading her that she needs to confront her deepest fears, he takes her to a cabin in a forest called (ahem!) Eden. But Nature – not least human nature – behaves very strangely there, and the trip proves the worst wilderness retreat since The Blair Witch Project.

Despite the trappings of genre horror, Antichrist is really a two-hander chamber drama, inspired by von Trier's beloved Strindberg. The film is very Bergman-like – especially early on, with the couple contemplating their situation in a register of muted intimacy that offers the film's only real drama. But once the cottage's handy toolbox is opened and the couple embark on the marital tiff to end them all, the drama instantly evaporates. The extremity of the violence is one thing: you look away or cross your legs, but you also gasp in disbelief that von Trier should resort to shock tactics straight out of Saw. But the brutality is also too graphically overstated to have real meaning: I won't spoil the surprise (or your breakfast) by describing the ejaculation scene, but sheer implausibility robs it of any effect other than gross-out revulsion.

Above all, there's little emotional logic. When the mother turns vengeful fury, it comes out of the blue: you don't feel that an emotional dam has burst, just that von Trier has got bored and cut to the chase. And it seems a waste of fine actors to have them vault into fortissimo and stay there. You can't fault Charlotte Gainsbourg for lack of restraint: when her character throws herself naked on the forest floor in a masturbatory frenzy, you can't help thinking: her old dad Serge would be so proud if he could see her now. The duo are at their best in the early scenes, tentatively stepping around the character's emotions: Dafoe is good being the tight-arsed, controlling rationalist, revealing himself in what he hides.

Antichrist contains some undeniable visual invention, with cinematographer Anthony Dod Mantle achieving some extraordinary effects: the creeping zoom on the decay in a vase of flowers; a hauntingly strange Bosch-like vista of buried multitudes. But a lot is at once beautiful and bad. The super-slow-motion prologue, detailing the child's death, is cynically manipulative in the cheapest, most obviously nerve-jangling way: the shot of a teddy bear hitting the snowy ground is egregious kitsch, all the worse for being set to a Handel lament. The sequence's pompous beauty reminded me of an early 1990s Sting video.

Von Trier claims that Antichrist stems directly from the deepest abyss of his unconscious. Even so, the film feels not like a genuine cri de coeur but like a contrived, detached experiment in extremity. Interestingly, the end titles credit researchers into misogyny, anxiety and even horror. This rather suggests that Von Trier has neither a knowledge of nor a genuine interest in the horror genre, that he needed someone around to say to him, "Interestingly, horror stories often express deep-seated fears and taboo desires – and by the way, you might want to take a look at the castration metaphors in Misery."

Antichrist has been accused of extreme misogyny, and it's true that Gainsbourg's character emerges as a figure of female emotion taken to a monstrous and incontinent extreme. But equally Dafoe stands for man as a repressed and repressing patriarch (and a crashing bore, with all his dreary psychodrama exercises). As for depicting the eternal conflict between man and woman, or mind and libido, or culture and nature – fair enough, but the dialogue keeps telling us, in a glum symposium-like manner, that the film is about these very themes.

The crossover between horror and art cinema can be fruitful: Kubrick achieved a mesmerising study of sexual conflict in The Shining; Bergman himself used the language of nightmare in a film both terrifying and deeply poetic, Hour of the Wolf. Antichrist convinces neither as chiller nor as auteur statement. It's simply a bad film: the sort of bad film, alas, that only a director of brilliance can make.