It was amazing, and the endgame was so much more than I expected! Great atmosphere, art direction, music, background sounds, voice acting—everything, really. I got stuck on a few puzzles (like the battery charging one), but that was on me; it felt great to solve them without hand-holding - that’s part of the thrill :)
Just one nitpick: the SMG recoil might be a bit too strong, though to be fair, shooting in short bursts makes it much more manageable.
What more can I say? It feels just like System Shock 2!