Caught this film in about 1990 on video by chance and without knowing what i was in for. Many horror fans may have missed this thinking it was a typical prison film and the ones who did get it didn't like it as it was not what they wanted to see. The above mentioned factors are probably the reasons it is low rated but just ignore that and give it a whirl if you're a fan of the genre.
It has strong suits in all departments from script and atmosphere to acting and the prison itself.
An absolute diamond, a film i still have on video to this day. Check it out.