The most recently purchased game that I beat (aside from multiplayer only stuff like Deep Rock Galactic) would be Black Mesa. Motivation to see the overhaul of xen at the end of the game really kept me going.

I recently beat Fallout 1 again, but I was using a high intelligence, high luck gambing critical hit sniper so it was more like an experiment to break the game. I’m in the middle of a 1 intelligence playthrough and its challenging but becoming a bit routine now that I’ve overcome early hurdles.