Halloween has been a gone but don't let that stop you trying out a new horror game, as Dream Well recently released with Linux support.
This is the first chapter in a planned series of four. It looks and sounds quite interesting, with a claim of an AI that learns to hunt you down requiring a stealthy approach. It also has procedural music, a responsive environment and incremental difficulty with a growing narrative—not that they explain what much of that actually means for the gameplay as it all sounds like fancy buzzwords to me.
While there's only one part released so far giving what they say is 1-2 hours play-time, buying a copy will give you the rest of the parts as free updates. Going by what else they said, it sounds like a demo might be in the works too so you can get a taste.
You can find it on itch.io.