wallpaper from S.T.A.L.K.E.R.: Shadow of Chernobyl (2007) © GSC Gameworld . In some games, nukes are just weapons (such as: Mass Effect ; DEFCON ; CIVILIZATION ). In others, nuclear holocausts spawn new worlds, populated by mutants. Two big game franchises in this branch of survival horror are the S.T.A.L.K.E.R. series (