Really cool concept, I loved going through the different puzzles!
One thing I would have added though: an undo button. It feels a bit tidious to restart the longer levels for a single mistake.
Other than that, the overall feel of the game is great: it's relaxing, challenging, introduces elements at a good pace, and has nice visuals. Plus, you made a lot of levels to really explore your idea, I played it for quite some time.
Finally, a detail that I loved was the title: it is cleverly used to introduce all the elements.
Very good job!