I love how the visuals, sounds, and animations all sell this lovely and fun mood that makes the game all that more enjoyable. I kept thinking I was in like a Mario Sunshine level when Flood is taken away from him but with its own unique style. :D
Continue to work on this idea. I want to see more clever uses of the mechanic. (I did not get to the final level so if you did add this already sorry :P) Maybe add more variations of the ducks like one that explodes when colliding with something so that it can destroy walls. Another one that cuts like blade which you can use to cut ropes to form bidges. These would be like a sacrificial ones to open the path for the yellow duck. Also, maybe fans that turn on/off on a timer.
Any who, clever idea, fun puzzles, really enjoyed it!