The game takes place in 2012.
It is sequence to S.T.A.L.K.E.R. Shadow of Chernobyl.
It's considered as the most successful game from S.T.A.L.K.E.R. franchise with more then 2 million copies sold.
Almost all locations that player can visit in game exist in real-life Chernobyl Exclusion Zone, including identical buildings and similar objects.
The end of game depends on your progress and decisions made through it.