Half-Life is a science fiction first-person shooter video game developed by Valve Software and the company's debut product.
Most of the game is set in a remote desert area of New Mexico in the Black Mesa Research Facility, a fictional complex that bears many similarities to both the Los Alamos National Laboratory and Area 51, between the years 2000 and 2009. The game's protagonist is the theoretical physicist Gordon Freeman, a graduate of the Institute for Experimental Physics and the University of Innsbruck, in Innsbruck, Austria, and Doctor of Philosophy in theoretical physics via MIT. Freeman becomes one of the survivors of an experiment at Black Mesa that goes horribly wrong, when an unexpected "resonance cascade" – a fictitious phenomenon – rips dimensional seams, devastating the facility. Aliens from another world—known as Xen—subsequently enter the facility through these dimensional seams (an event known as the "Black Mesa incident").[12]
As Freeman tries to make his way out of the ruined facility to find help for the injured, he soon discovers that he is caught between two sides: the hostile aliens and the Hazardous Environment Combat Unit, a United States Marine Corps Special Forces division dispatched to cover up the incident by eliminating the aliens, as well as Dr. Freeman and the other surviving Black Mesa personnel. Throughout the game, a mysterious figure known (but not actually referred to in-game) as "G-Man" regularly appears, and seems to be monitoring Freeman's progress. Ultimately, Freeman uses the cooperation of surviving scientists and security officers to work his way towards the mysterious "Lambda Complex" of Black Mesa (signified with the Greek "λ" character), where a team of survivors teleport him to the alien world Xen to kill the Nihilanth, the creature keeping Xen's side of the dimensional rift open.[12]
http://en.wikipedia.org/wiki/Half_life_(game)
Best game ever, best plot, best game play, just the best.