This is genuinely creepy. I love being scared in that sense of having to shut my eyes for a second because I'm certain something terrifying is about to jump out at me. (I watched it a second time, keeping my eyes open.)
I think the audio is what made it scary. When I read that some of the audio was just your voice slowed down to a hum, I was really impressed. Adding that on top of the rest of the audio really brought things together.
The only reason I didn't give you 5/5 was because I think maybe you could make it longer, and maybe add that "jump-scare."
Overall though, I loved it.