The stand-alone mod S.T.A.L.K.E.R. Anomaly aims to be the most stable and customizable experience for fans of the S.T.A.L.K.E.R. games. It's powered by the Monolith 64-bit engine, a custom fork of the X-Ray engine.
Players voiced reaction to game events. Works with RC22, NZK, Provaks weapon overhaul etc, not sure about previous builds.