"All Night Long R" was released on DVD only in Japan, but I managed to track it down. The film is not as savagely violent as the previous two movies "All Night Long 2" and "All Night Long 3", but the tone of it is definitely disturbing and depressing. It tells us about obviously disturbed Japanese individual named Yuuki who captures two Japanese girls. One of them, Reika,is brutally murdered and her captor cuts her up and takes her body parts like ears and breast.The second girl is chained to his bed and he performs a hideous experiments on her body. "All Night Long R" is a rather slow-moving horror film that offers plenty of shocking violence.The acting is excellent and the killing of a Japanese boy is extremely vicious and cruel. Sometimes the film has a mood of a very sad romance. So if you're a fan of Katsuya Matsumura's works give this gem a look.
The third and final chapter in the disturbing All Night Long series tells the tale of a teenager who becomes obsessed with his attractive neighbor a fellow student. His infatuation grows more and more disturbing as he begins going through her garbage eating her discarded food and eventually begins doing things in direct violation with the law.