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.
It's an amazing game for the time it was made in, and the gameplay is excellent. The NPCs and enemies can be kind of dumb, though. However, you can expect that from a first-person shooter back then. It's amazing pace, and unique story elements have driven me to this vote, and I thank Valve for making such a great game.