We are being invaded by Martians, who want to exterminate the human race to inhabit the planet ... fight to defend the earth. Martian invasion, alien invasion, space shooter, arcade game, action game, hypercasual, retro game, defend earth, extermination, space battle, alien fight, touch screen game, gameplay, exterminate, planet defense, space combat, save humanity, extraterrestrial invaders, classic arcade, mobile game