Starting with the positive, the cinematography is new and interesting, especially the forest scenes. The acting is flat - almost cardboard. Once in the movie Dafoe shows emotion. Gainsbourg bounces between stark raving mad and manic depressive - with hardly a personality between.
The rest of this mess stands on its close-up sexuality and violence. The "study" of misogyny, which it pretends to, ends with a scene of a half-baked excuse for killing. To further confuse that, we have nude people, mostly women, oddly clothed in the final scene, haunting the forest, and guess who lumbering off.
Give von Trier credit for showing us that a forest ("nature") - often Disneyfied as idyllic - can be a sad if not deeply disturbing place.