FPS titles with great environmental world-building? e.g. Alien: Isolation, Metro, DOOM '16, even Portal 2 counts -- games that feel like real, lived-in places and not just a series of arenas.
For example, I didn't fall in love with Titanfall 2's environmental art design---it felt a bit generic to me, like it was meant to be the backdrop for a shooter, as opposed to the Sevastopol in A:I or the station in SOMA that felt like existing locations.
Ditto BioShock: Infinite. The world felt like it was built around the premise of being an arena shooter, not the other way around.
BioShock 1 & 2 are exactly what I'm talking about though.
Even Borderlands 2 has great world-building: the corporate history that can be inferred from the level design, the weapons & the NPCs makes it one of the richer games I've played.
Would love to hear others' thoughts on your favorite FPS environments!