Stalker was amazing. I beat every single Stalker game and made sure to do so meticulously and thoroughly. I cannot bring myself to play any of the Stalker Gamma mods as those came way, way too late for me.
Definitely looking forward to Stalker 2, but also Pioneer which should be absolutely insane as well as the next Metro game which was just announced.
For anyone who wants a dose of Soviet/Russian/Post-Apocalyptic to hold you over, I strongly recommend Atomic Heart. There's been plenty of criticism, but those people are fools. Ignore them. The game is amazing minus a few quirks only a Russian native speaker would take issue with due to some incorrect cultural... stuff...