Goretech: Welcome To Planet M*therfucker (2012)

Earth succumbed to a nuclear war caused by an infamous evil being known as Dr Hell, who today dominates the world with his technology from a distant planet called Goretech. Now the world is only violence and death and humanity is inexorably approaching its extinction, as there are no women left alive. A timorous and cowardly young man named Han meets a mythical curmudgeonly old man who will teach him the secret of martial arts, and together they will fight to end the tyranny of the sinister Dr Hell.