Jesse Johnson’s “Alien Agent” is less a sci-fi movie about invading aliens as it’s a martial arts movie with invading aliens. The film stars Mark Dacascos as the alien agent of the title, sent to Earth to stop an alien renegade military unit from creating a “gateway” that would connect Earth to their alien homeworld, after which they would use the portal to invade Earth. For you see, their homeworld is dying, and they need a replacement. While the good alien folks back home are willing to search for an uninhabited planet to start over again, Billy Zane and company are not so nice, and plans to invade Earth.