This film certainly deserves to be better known. I think with gay cinema evaluations have to be made in the context of the era in which they were made. The simplicity, honesty, brutality, and directness of this story is exceptional for the time.
It's a slender story, familiar yet different. Familiar insofar as the difficulty of maintaining a same sex relationship, especially when there is a significant age difference. But different in that it deals with a harsh (and somewhat incomprehensible) penal system. Nevertheless, American gay men will be able to relate, and translating 1970s Switzerland/Germany to a similar present-day experience will not be difficult at all. Unfortunately for us, this is a story I'm sure is happening every day all around the world.
It's fascinating to see a younger Jurgen Prochnow. The other lead, the beautiful young man, was and is unknown to me, but his performance is exactly right. All the performances are spot on, in fact.
If there is an amateurish aspect to this film, it's the uneven (sometimes) grainy photography. Perhaps it was shot on 16mm and blown up. The subtitles (on the Netflix version I saw) are white, and impossible to read whenever they fall on a white background. That happens a lot, unfortunately. This is a movie that deserves better.
Definitely worth seeing.