You did an amazing job introducing and building on mechanics. The final level and needing to utilize perfect timing and everything learned previously to bring that waterfall down all the way was perfect (and very tough, I retried it so many times!).
You've got a real talent for puzzle design and I thought the art and sounds fit the game well. If you ever wanted to continue expanding on the premise and build on the visuals/sound to suit a larger audience I think you could have a real hit! Axolotls are such a great character to work with too!
Great work! Really enjoyed playing it. Only complaint is I accidentally completed the final screen before seeing what it said :D