S.T.A.L.K.E.R.: Clear Sky Downloadable Exclusively on Steam
S.T.A.L.K.E.R.: Clear Sky is the official prequel to THQ's survival FPS S.T.A.L.K.E.R.: Shadow of Chernobyl, bringing the players one year prior to the events of the original S.T.A.L.K.E.R. game in 2011. Valve has signed a worldwide digital download exclusivity agreement with GCS Game World.