Playing Line of Sight: Vietnam.
A rather obscure game, this one can be pretty rough. Trying to do a flawless no death run, but it's really hard. Snipers everywhere, hidden Viet Cong in the jungle...
Hello PTSD!
I have kind of a cool memory of playing the first area/level of this game when it came out. Was traversing through the thick thick foliage of the jungle and suddenly came across an open bunker of vietcong. Instead of instantly and robotically firing at me and hitscanning me, they all just stood there for a second, staring at me, mouths agape, seeming to be as surprised by me as I was by them.
Then they started firing. Never finished the game but it was an unexpected, immersive moment of the type I hadn't experienced in an FPS before.