Successfully getting an artifact in S.T.A.L.K.E.R. without taking any damage or dying
yo i totally forgot about Stalker
For all its faults, Clear Sky's ending sequence was one of the best I've ever played.
Call of Pripyat's final act with the soldiers stranded in Pripyat was really cool too, since it was the first time you get to work with the military in the zone.
CoP water treatment facility. CoP weapon trade mission. CoP mercenary ambush. CoP had a lot of great moments.
The first controller in SoC. Never climbed up a ladder faster than I did there.
The entirety of the first X Lab, with the soldiers in SoC. On that note, the hotel lab in CoP. I like the labs.