It is one of the purest “reality + weird things” settings available. It has an open, internally-consistent world. Play SoC first, CoP second and CS only if you still don’t have enough. I’d recommend playing CoP first, it being the most polished and easiest to get into, then going for SoC and Clear Sky. So, it pretty much goes in the same succession as they were released. Yeah, as some have mentioned, start with Shadow of Chernobyl, while Clear Sky is a prequel, gameplay wise it is closer to Call of Pripyat (which is in that regard the best out of the three). The Stalker 2 release date is April 28, 2022. Totally worth it, but I recommend installing some mods that enhance the graphics and gunplay. The gameplay is the least “STALKER-like” of the 3 games, and generally it does not have as many mods as SoC or CoP. Developer GSC Game World’s most excellent first person survival horror/RPG-ish hybrid Shadow of Chernobyl is FREE (feeling the emphasis yet?) to play on.
S.T.A.L.K.E.R: Shadow of Chernobyl available for FREE on.