Use this mod to get appropriate reverb effects when using OpenAL Soft. It features 32 explorable maps, reworked level design and level fixes, new original level, Trucks Cemetery, Full AI and A-Life overhaul, engine and script enhancements, Repeatable task system which bases itself on A-Life events, Customizable weather environments for every map as well as surges and psi-storms from AF3, Character creation which includes name, portrait and faction selection Several optional modes such as Ironman mode, story mode and zombie survival mode, New achievements, rankings and reputation system, PDA leaderboard and enhanced PDA statistics, Companion system with keyboard issued commands, many optional side-features and community-made addons.
Play the 3 games in order of release (Shadow of Chernobyl, Clear Sky and Call of Pripyat) then come back for the mods.
Mod DB has an large list of mods available for S.T.A.L.K.E.R.: Call of Pripyat.