Granted, there are some really creepy moments in the game. Just get the expectation out of your head that this is a horror game, and you'll enjoy it much more.
If you've never had any prior experience with changing the soundfont on Windows 10 or 8.1 (M$ likes to make things really complicated for some reason), or if you've never had experience with soundfonts in general, this guide will help you a lot: I REALLY REALLY recommend using ChoriumRevA I personally found it to be the best soundfont, after trying several different soundfonts.
Regarding the music, make sure to use a soundfont that isn't the default one on Windows. I never considered system shock a horror game, personally, but it is one of the best games I played in my entire life, regardless of the genre.
