Named Game of the Year by over 50 publications, Valve's début title blends action and adventure with award-winning technology to create a frighteningly realistic world where players must think to survive. Also includes an exciting multiplayer mode that allows you to play against friends and enemies around the world.
After the Xen incident, the scientist built a base on one of xen's moons, and sent soldiers there but somewhere on the way the commander decided to keep the base for himself. You are ordered to go there to stop him.
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