Yeah, I said it. I've played a lot of "horror" themed games that were supposed to be scary. Sure, a few made me feel a little tense, and I thought it was as cool as anyone when that first zombie turned its head in Resident Evil, but none of them actually made me afraid. Not like "oh shit that thing is coming for me" afraid. Only one game ever legitimately did that, System Shock 2. And holy shit and bananas, it's finally available out there in digital form from our friends at GOG.com.
Granted I haven't played this game in probably 10 years at least. Heck, I haven't REALLY played it since about 2000, shortly after its release. I actually tried once about 5 years back, as I still had my old copy, but couldn't get the dang thing to work right. So I gave up.
Now I'm sure that there will be quite a few people that are completely turned off by the dated visuals and/or dated gameplay. Remember that the FPS wasn't really a "thing" when this came out. Control schemes, feel, and all that were still up in the air, not cemented like they are now. Things are going to feel clunky, it's not going to be anywhere near as polished as Bioshock (its spiritual successor,) and it altogether will feel like a 14-year-old game.
But don't be an asshole. It is old, old but very well-regarded. And trust me when I say we weren't idiots back then, we could spot good games. And this one was great. I think once you know about "the many" you'll agree. Now shell out the 10 bucks and play.