fronzelneekburm: There's quite a bit of overlap between our favourites, these in particular I love:
heartburnron: System Shock 1 & 2
Deus Ex (Original)
Postal 2
S.T.A.L.K.E.R games
The Saboteur
fronzelneekburm: With that in mind, here are some suggestions:
The Thief series You want scary? Play Thief.
The Hitman series Contracts is a nightmare-fueled retelling of the first game, I consider it one of the most atmospheric games I've ever played.
Kingpin - Life Of Crime Severely underrated FPS gem with graphics that still look surprisingly nice today, great sound design and a quite remarkable AI (while Half-Life's highly praised AI mostly succeeded in ways to get stuck in the level architecture, Kingpin's NPCs can jump, duck, crawl through vents, climb up ladders,...) Don't play this like your average shooter, keep your weapon holstered unless you're attacked first and be friendly towards the NPCs, chances are you'll live longer.
There's lots of more great games to suggest (the years from 1997-2000 were pretty much the golden age of PC gaming), but the Thief series alone should last you for a while. :D
Thanks - I wouldn't have said I was the biggest fan of predominantly stealth based games, in Dishonoured for example I got a bit bored of stealthing about and preferred to go in all guns blazing at times and for this reason I had dismissed the Thief games, or the most recent ones anyway. However, that changes when there is a horror element to it. I would never have considered the Thief games to be scary so thanks for that - I'll check those out in future.
I got the most recent Hitman game free with a graphics card last year and whilst I did enjoy the first few levels I don't really have the patience for all the strategic planning required in the game. I definitely wouldn't have described that game as atmospheric though, I take the original games feel different then?
Never heard of Kingpin but I like the sound of the AI you've described. Cheers.