This is Lars von Trier's Antichrist – a film in which the virtues of therapy are tossed on the grill to sizzle alongside womanly sin, Satanism, lust, Bacchic worship, bereavement and an assortment of self-consciously symbolic woodland animals. It would be quite the barbeque even without the Reggae Reggae Sauce of graphic copulation and dick-shrivelling sexual violence.

An arrogant, controlling therapist attempts to chaperone his glib academic wife through the grief of losing their own son by travelling to an isolated woodland shack (of course!) where her fears culminate and their relationship takes on a new, and entirely hideous meaning. He's Willem Dafoe – or at least something that might have been Willem Dafoe prior to centuries of preservation in a peat bog, compressing his wizened face into a yet more stoically creased Dafoe omelette. She, meanwhile, is an unpleasantly sinewy, waif-like golem of passing resemblance to Charlotte Gainsbourg. It's hard to enjoy these gristly forms rutting with each other, as they so often do throughout the film – their bestiality compounding the film's assertion that there is something grotesque and noxious about the animal, natural world.

(I speak only for myself, of course. Such qualms were not for the man five feet to my right, who was, with ineffectual furtiveness, tugging one out right there in the cinema, belt buckle jangling. Bath is such a genteel city.)

A tad flabby, stagey and a little infatuated with its own sense of portent, Antichrist isn't a great film – but its smarts do dispel the accusation that it's just Saw for the goatee-beard crowd. The question, posed by at least one too many talking foxes, is how seriously should we really take it? Is its atmosphere of slightly over-egged unheimlich in earnest, or is it edging into the absurd?

(Spoilers ahead...)

If there is a joke here, it's partly on the audience, but in a weird, self-effacing way, it seems to be on von Trier as well. A sufferer of chronic, paralysing bouts of depression, von Trier has publicly endorsed the methods of therapy that here seem so ineffectual, laughable. Willem Dafoe's infuriatingly placid attempts to get his near-rabid wife to map out her “fear pyramid” seem just as daft as the dictums so solemnly held by the disability-faking Idiots of von Trier's earlier film. And then there's the aborted thesis written by Gainsbourg's character – 'Gynocide', a dissertation on the persecution of women as witches that begins as a rationalist, feminist indictment and then derails with the epiphany that maybe women really are touched by some terrible original sin. It's a pattern mimicked by the film as a whole: what sets out to be an artfully shot, beret-wearing examination of grief through the lens of therapy, suddenly devolves into a bonkers slasher flick of toe-curling extremity in its last half, and ultimately posits that women and nature are indeed the tools of Satan. But I suppose that's corruption for you: going from arthouse to Eli Roth in just over one hundred minutes.

In short: gosh!