"In fact if you want to give a deeper reading of the film, it can be seen as a vaguely lesbian story; where lesbianism has a certain importance. Or, more precisely, where the relationships between women are sometimes of a lesbian nature and are characterised by power struggles. But because society at the time was more prudish than today, I couldn't fully express the lesbian theme and I really regret this."
That's Dario Argento rebutting the argument that he is a misogynist. And it's true that the film's male characters are largely ineffectual. The people that carry the story (such as it is) forwards are all women – the children lost in the dark woods of Germany, and the wicked witches to be found within. One of the (female) critics on the DVD denied that the nubile girls under threat are objectified by the camera, but personally I think that's a difficult argument to make with all the swimsuits, tight jumpers and loose bathrobes in the film.
The quote above seems to elide the power struggle and the desire between the older and younger women. Perhaps the former arises out of the latter, but in any case it's hardly a healthy portrayal of lesbianism. The motives of the witches are unexplained, but the simplest reading might be that the superpowered crone at the head of the coven resents the youth and beauty of the children at her ballet school. This drives her to murder those who try to escape her clutches, or uncover her embarrassingly depleted self.
But I'm over-analysing, because the film doesn't operate by the standards of plot-driven giallo. Empiricism is chucked out of the window by the professor who insists that magic is all around us. Maybe not in the real world, but the magic of cinema is certainly omnipresent in the film. Lighting, framing and music invade and overshadow the narrative completely. The story is just the means by which Argento conducts a series of experiments with his band and his cinematographer in building tension and release.
And it has dated horribly – the direction and soundtrack are so in your face that you are never allowed to sink into the situation and genuinely experience the terror inherent in it. Instead the film feels ridiculous, nowhere more so than when one of the victims foolishly jumps into a mass of razorwire in fleeing her assailant. In fact, the film's structure is rather repetitive – being a series of discreet sequences that lead to an improbably bloody murder. Describing it as pornographic is not actually that wide off the mark, in that it's flat, predictable, and a little bit dull.