It sounds like FPS fans may have more S.T.A.L.K.E.R. to look forward to as GSC Game World is reportedly working on a second expansion to the hit 2007 shooter for release later this year.
Translations of a Russian interview with GSC Game World President Sergey Grigorovitch have revealed that the company is currently developing a second "stand-alone expansion" called S.T.A.L.K.E.R.: Call of Pripyat. Apparently the April 2009 S.T.A.L.K.E.R. calendar included the words "Call of Pripyat" in Russian underneath the S.T.A.L.K.E.R. logo and when Grigorovitch was asked whether it was an April Fool's joke he replied that it was in fact the name of the second expansion, scheduled for release this fall.
Despite being the first "expansion" in the series, S.T.A.L.K.E.R.: Clear Sky is actually a stand-alone prequel that doesn't require the original game to operate and the assumption at this point is that Call of Pripyat will be the same. Grigorovitch also indicated that an all-new S.T.A.L.K.E.R. game was in the works, although how it would tie in with the first game and when it's expected to be released is unknown.
No official announcement has been made so for now this is just a rumor. We've dropped a line to GSC Game World asking for confirmation and will update when we can.