The atmosphere you are starting to create is really good! Very on point for what little there is to go on so far, knowing that this is just the very basic groundwork for what I'm assuming is going to be a larger game.
Some things to consider/keep in mind while moving forward with this project: there are three very important pieces to the horror genre (in terms of audio/visual media), which are pacing, story, and sound design. Don't be afraid to use silence and background noise to your advantage. What is the story you are trying to tell? Is it one that is important to you? Why? What makes a horror story compelling, at least to me, is what it says about the human condition. The perspective that you add to that through the story you're telling is what will make the game stand out. Finally, watch your pacing. I say this as a advice from someone who has had to work through pacing issues in my own writing lmao. Pacing matters in most media, but horror especially because you're trying to build suspense so that the scares hit harder when they come. I've also stalled in several horror games due to frustration when the game's mechanics overshadowed the story.
Anyway, apologies for writing a novel here lmao. I just really love the genre, and genuinely want to help if I can. You might know all this already, and obviously will have your own ideas about what works. Either way, I really look forward to seeing what you come up with!