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.
Unripe or not fully developed. Immature, unfinished, incomplete. (But the map packs are complete though. Playable from start to finish. It's a story about the adventure of an unnamed scientist that change his life from the pickup of an HEV suit from an accident to defeating an evil alien boss.