Nice job! I really like the atmosphere, it's a nice fog and environment and the music is really pleasant. I also really like the design of the key model.
I did have a difficult time because I kept getting hit and stuck floating off the ground, so I couldn't interact with things. At one point I was riding the goat enemy for a while, which was pretty fun. I was also disappointed to learn that the music didn't loop, which would have been really nice. Otherwise I would say the sfx are a lot louder than the music, which could end up hurting someones ears if they have their volume higher than I did.
I think it's a really nice concept with a cool style, good work!