S.T.A.L.K.E.R.: Shadow of Chernobyl

'S.T.A.L.K.E.R.: Shadow of Chernobyl, previously known as S.T.A.L.K.E.R.: Oblivion Lost, is a first-person shooter computer game by the Ukrainian developer GSC Game World, published in 2007. It features an alternate reality theme, where a second nuclear disaster occurs at the Chernobyl Nuclear Power Plant in the near future and causes strange changes in the area around it. The game has a non-linear storyline and features gameplay elements such as trading and two-way communication with NPCs. The game includes elements of role-playing and business simulation games.

The background and some terminology of the game ("The Zone", "Stalker") is borrowed from the popular science fiction novella Roadside Picnic by Boris and Arkady Strugatsky and the 1979 Andrei Tarkovsky film Stalker that was loosely based on it, as well as Stalker, the film's subsequent novelization by the original authors.

On July 11, 2007, GSC Game World announced a prequel, S.T.A.L.K.E.R.: Clear Sky, which was released on September 5, 2008. On April 30, 2009, GSC Game World announced a sequel, S.T.A.L.K.E.R.: Call of Pripyat, which was released in February 2010.

In S.T.A.L.K.E.R, the player assumes the identity of an amnesiac "Stalker", an illegal explorer/artifact scavenger in "The Zone", named "The Marked One". The Zone is the location of an alternate reality version of the Chernobyl Power Plant after a second, fictitious explosion, which contaminated the surrounding area with radiation and caused strange otherworldly changes in local fauna, flora and the laws of physics. Stalker, in the context of the film, refers to the older meaning of the word as a tracker and hunter of game, or a guide.

S.T.A.L.K.E.R. stands for "Scavenger, Trespasser, Adventurer, Loner, Killer, Explorer, Robber".