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.
Brutal, eerie, and chilling, Shadow of Chernobyl jump-started the S.T.A.L.K.E.R. series which has earned quite the cult following. An excellent story lies underneath the hellish Zone, and the hardcore gameplay mechanics are very good. S.T.A.L.K.E.R. offers more modding capabilities than pretty much any game out there, save the Crysis games, and the community is very active so this is a game that will sustain throughout the years. It's definitely the best of the series.