Yeah, the graphics were honestly kinda underwhelming, in particular the models were behind the curve compared to contemporary titles like Half-Life, and this didn't really improve with later titles like System Shock 2, where half the horror was the distorted textures stretched across the faces of the models.

I think what modern games have lost, that some of these late 90s titles absolutely nailed (Thief in particular), is the sound design and ambiance, which is just so dang evocative. Even the smallest incidental sounds had so much character. Picking up an item, pulling a lever, footsteps on the floor.

Modern games use such flat sounds for everything. Sure it's more realistic, at the cost of character and vibe.

I never played Thief, so I can't compare two. I was really impressed w/ System Shock 2.

re: the graphics - I don't remember being particularly underwhelmed by the graphics, but I didn't play many contemporary titles to compare it to. I was drawn-in by the System Shock franchise, but otherwise didn't really game.

For me the horror element came from the voice acting on the audio journals, the voices of "the many", and those goddamned cyborg assassins.