Renny Harlin's second feature is a well made supernatural horror film that is much better than what you'd think. Sure, the film looks a bit dated nowadays, and there's been far better ghost tales than this, but in the long run, Prison is a surprising, accomplished film that is an obscured genre film that should see the light of day. The cast do a good job here, but the standout aspects of the film are the special effects, the kill sequences as the supernatural force kills prison inmates and guards alike. Renny Harlin, who has a checkered career, pulls off a good, entertaining and enjoyable ride. This is a pleasant flick to watch for horror fans that enjoy a good ghost story. Although there's never anything truly great on-screen, there are enough good bits here and there throughout the film to make it an enjoyable yarn to simply sit back and enjoy. The plot was original and it's what kept me interested in the film, unlike Kevin VanHook's Death Row, which uses basically the same premise as this movie, this is a far better film that is good gory fun. Despite its lacking acting, the film is held together by effective directing for Harlin. If you're ever looking for a fun little obscured gem of a horror tale, then pick this one out. The film is not perfect, but it has enough going for it to make it a worthwhile good time for genre fans. What makes this film good is the fact that you never see the supernatural force itself, and it leaves it up to your imagination to guess what kind of demented, evil supernatural force is terrorizing the prison. We know it's the prisoner that wants revenge, but you never see him, thus it makes for a more enjoyable viewing as it keeps you guessing till the very end.