Fantastic sound design! Inititally I was a bit put off by the contrast between the beautifully stylized fox and the very rudimentary level geometry, but once I got to the cave I understood what you were going for, and I think it works great.
That said, I didn't finish it. The bottomless pits just got too frustrating for me, and I stopped playing after I drowned for the first time. I assumed I could swim but spotted the moving platform just after I died. It would have helped to have been introduced to moving geometry a little bit earlier. I also found a secret earlier in the game, but mostly by accident, and I wouldn't go out of my way to look for more. The fear of getting sent back to the start is too strong.
Still, this is lovely! I'm gonna be thinking about that cave for a while, it really left an impression on me.