Grab your shotgun, space marine! A portal to Hell itself has been opened on Mars and an army of demons are overrunning the colony! Nearly everyone has been killed or possessed and you are the last line of defence before they find a way to reach Earth! Frantic, fast-paced action awaits as you rip and tear your way through the demonic hordes, but be careful! You may have access to some of the most advanced weaponry humanity has ever developed, but they have learned to use it as well.