Really cool idea! As a rhythm game enthusiast myself, I was really suprised to see something like this done, and also done so well! Sadly, I struggled with figuring out when exactly a click was seen as a miss, good, perfect or anything at all, since the "perfect" window seemed to be right at the beginning of each step, which took a while to figure out.
I think this idea (I don't even wanna talk about the excellent atmosphere, horror elements, and neat visuals, especially the hand and heart), when expanded upon and improved, could become a really, really nice game. (Also, I found it relatively annoying to move sometimes, especially in long corridors, because I always had to wait a full cycle before being able to move forward again... Maybe include a second forward option or something?)
So yeah, I'd really like to see this turned into a grown-out game, but think this is already pretty cool.
Have a nice day :3