Prey is _the_ high watermark for this kind of game, I was so surprised to hear what a commercial failure it was, but it's such a work of art. The sense of exploration, dread & mystery, the weirdness of finding the first ending, then the next ending, then the next...

And yeah, I started replaying Bioshock a few weeks back - aesthetic is still lush but it's thin, much more of a combat game - you have to git gud more than I remember.