Original: 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 .
Simplified: S.T.A.L.K.E.R. : Shadow of Chernobyl , previously known as S.T.A.L.K.E.R. : Oblivion Lost , is a post-apocalyptic first-person shooter computer game by Ukrainian developer GSC Game World .