Alien Shooter is a top-down, Isometric Shoot'Em Up by indie developer Sigma Team, released in 2003 for the PC and later made availible through Steam in 2009. An Updated Rerelease, Alien Shooter: Revisited, was also released in 2009, featuring more levels and an extra game mode. Here's the lowdown: A top-secret Elaborate Underground Base has been infested with hostile alien creatures. All on-site personnel have been killed. You, a crack government operative and literal One-Man Army (Or Woman, your choice) have been sent in to destroy the aliens. It's that simple.