It's about a man, who thinks he's a wolf. Which is silly because "you can’t be one wolf, you’re always eight or nine, six or seven". The movie is a victim of some of the excesses of the 70's. It starts out ok, as if it's going to be about pre-World War 2 Europe. But then it just devolves into a bad LSD movie with astoundingly bad special effects.
Von sydow is always interesting actor to watch but this is a very dated movie. Even in its day I can't imagine this being of much interest to anyone except the psychedelic crowd. Roeg's "Performance " did this sort of mind-fuck much better although it is kind of fascinating seeing the director trying and failing to find the visual equivalent of Hesse's masterpiece.
A brave effort that failed. Like many other attempts of adapting books that are a lot more than just an interesting story. It did try to be bold. But the language was a bit shy, or too silly, in its oniric incursions. Maybe Greenaway should have done it. He would not have shy away from creating something new and would just forget about filming "the story of the book". And that would probably work a lot better.