Graphically very nice. I loved the sound getting more layered as it went up, gave a nice sense of progression.
I would have liked a better indicator where exactly I was in the world. The light rays were a bit of help, but somehow it wasn't has useful as I was hoping. I think the shadow cast could have been greater, maybe?
The place with all the black monsters, I kept dying for no reason. Maybe they have some ability I don't know about, or it's just a bug. It stopped me from progressing further though.
Overall great work. Really fun, chill game!