"S.T.A.L.K.E.R.: Clear Sky" is a first-person shooter video game developed by GSC Game World, released in 2008. It serves as a prequel to the original game, "S.T.A.L.K.E.R.: Shadow of Chernobyl," and is set in the Chernobyl Exclusion Zone. Players explore a post-apocalyptic world filled with mutants, anomalies, and rival factions. The game features an open-world environment, allowing players to complete quests and engage in combat with various enemies. It introduces a faction system, where players can align with different groups, influencing the game's outcome. The immersive atmosphere and survival elements enhance the overall experience.