These comments are based on watching the UK DVD release from which most of the series' sexual violence has removed. This version was also dubbed into English with no option of watching in Japanese with subtitles.
After the Earth is struck by a comet Japan descends into lawlessness; most of the infrastructure is destroyed and the survivors become victims or oppressors. This series of three stories each feature the eponymous Violence Jack; a brutal giant of a man who uses his great strength to help the weak and brutalised. Whether it is under the wreckage of Tokyo or across the Kanto plain there will always be murderers and rapists for Jack to kill!
Given its title it is no surprise that these series is very violent at times and the sexual nature of some of that, even in the cut version, is somewhat disturbing. That said the stories are entertaining with lots of action. Violence Jack is an unusual protagonist; he doesn't say very much but grunts and growls during his many violent encounters. The villains are definitely evil so one feels no sympathy when they meet their ends. The animation is decent enough for a series of this age and the characters' design style suits the nature of the story. Overall I wouldn't call this a classic but if you like older, more violent anime then it is worth watching.