If you want an FPS with some real weight and grit to it, look no further than Trepang2. Taking influence from FEAR and the newer Doom games, but pushing against the latter's raw power fantasy, it's a shooter that leaves an impression, and you can get it for an absolute bargain right now.
RELATED LINKS:
Now is the perfect time to play Trepang2, the greatest FPS to hit PC in years
Trepang2, Deathloop, Robocop, and more great FPS games now super cheap
Trepang2 is the best FPS I've played in years, and it just got better