The bests mods are indeed Russian, they lack translations but they're fucking awesome.
Fortunely we got stuff like STALKERSOUP, hardcore fans of STALKER will love this one, it's damn intense and its massive.
Game fucking wanna makes me stay in a safe place for the night, damn punishing, no geiger counter, no anomaly detector, no radiation protection, ammo is like gold, a good gun is like diamonds, everything looks dark, depressed, get shot and you're most likely dead, get caught by a bloodsucker and you will be his breakfast, find a chimera and you're his dinner, etc.
There's also a bunch of anomalies one doesn't know how they work, and some are too hard to see!, from nowhere BAM, a tornado or some weird looking plant coming out of nowhere kills you.
I don't know how large the game is actually, like how many missions does it have, but i started a long time ago and I'm still trying to find decent weaponry for the Agroprom Underground mission :/