This was cool! The minimalist audio suits the game well. I also liked the way you incorporated both the theme 'minimalism' and optional challenges into different elements of the game (from the art, sound, to back story) - they all work really well together.
I liked the aesthetic with the lighting / oncoming mist (as others have pointed out - it might be a bit dark, but you've mentioned you will update that which is awesome).
Looking forward to when you update it and expand on the game in the future! Overall great work :D