as many people have mentioned, pc version requires a fuckton of tinkering to get working, even if you purchase it on steam, which is quite unfortunate.
for the first playthrough i left this game quite disappointed with how linear and rough it gets, rooms more often then not only have one way to solve them, the game will force you into combat despite having a combat system purposefully build badly to force you to avoid it, so i ended up not liking it much.
then i played it again recently, not trying to play perfectly and just going half life on this bad boy, only to find out how JANK this is, try it, you can easily get out of bounds using the double jump and almost skip some rough areas, quickly crouching is as fast as running and does not make any noise, this game is jank enough that you can break it quite easily and have fun with bending the rules to your liking, fuck it, just shoot everyone, but make sure to hide the bodies in the dark, and thats only for a few selected missions, why even go through the trouble of hitting good scores ? you unlock NOTHING to do it, so just break this game up