Shin Hokuto no Ken, Kakugo no Susume Recommendations
Both titles are set in a post-apocalyptic setting after the earth was destroyed by a devastating event. The main protagonist in both anime uses martial arts to kill anyone that stands in their way. They are also both action-packed anime with lots of blood and gore. The differences between the two is that Apocalypse Zero is more over the top and has mutants for enemies while New Fist of the North Star has humans for enemies and has a better story. If you enjoy one, you should like the other as well.