I love how this game is puzzle and art-centric. It really does look beautiful, with a twinge of uncomfortable fantasy in regards to Mink. I feel like this adds to the game, however, as the forest is supposed to be dying and we're trying to save the king. It isn't a happy kingdom, and there are uncomfortable creatures like Mink within the fantasy realm. That being said, I don't feel the sound design was very accurate. Not many actions have a sound affect attached, and the sound for the game is a big consideration and should have more value put into it.
Take the level-select, for example. There is no audio for selecting a level, which just adds the slightest bit of immersion. While I think the song you chose is fine, it's a little repetitive in this context. If you changed this and updated it, however, it really would be a perfect game! You have a great concept on your hands, make it the best it can be! Again, it's very beautiful and the puzzles are fun to solve.