So, I did a let's play of your game, and I have mixed reactions to it. On one hand it had a good ambiance to it. By this I mean I liked the environment and lighting. Both contributed to the horror element.
On the other hand though, you only had a grand total of 3 scary moments (about), though I suppose you could sort of increase it to 5. Either way, I think you can add a lot more elements to it.
Also, if you're not going to let us go farther up or down, then I would recommend not keeping those pathways there. Instead of invisible walls, just put solid walls down.