In 1986, the world's worst nuclear disaster occurred at the Chernobyl power station. Soviet authorities established a 30km 'Exclusion Zone' around this nuclear wasteland, but in 2006 a second explosion rocked the stricken reactor, obliterating all living things and causing the Zone's boundaries to ripple outwards. From this epicenter came waves of mutated creatures, deadly radiation, and a strange, anomalous energy. The Zone was cordoned off by the military, who would shoot on sight anyone foolish enough to brave the horrors within.
One of the must atmospheric games I have ever played, and I would dare to say, ever made. When I first played this back in 2013, after ascending to PC I was blown away by the depth of the NPC's routines, the unpredictable game world, and the atmosphere.
I had not played anything like it at the time, with the closest thing to it being TES IV: Oblivion. The mix of the three listed attributes has made one of the greatest games available on PC. Do yourself a favor and pick it up.