I guess fantastical prison movies have been a thing in Japan since long before Story of Ricky. This one is as sleazy as a Roger Corman outing but ups the brutality of the guards to crazy levels. It's not terribly gory, just ruthless and hyper-stylized. The best scene is when a fellow prisoner goes nuts in the shower and the lighting plus the make-up turn her into a wild kabuki killer. There are apparently three more films in this series, so we'll see how far they are going to take things.