This is a great idea and I could definitely see this being a full game. The level design is really well thought out and the game wastes no time in showing off its shining qualities.
Some Quality Of Life I think some others have mentioned wouldn't go amiss such as a bar to show me how much growth I have left or an angry birds style trajectory indicator. But the lack of these in no way hampered my experience.
I really enjoyed this one and spent way longer playing than I'm willing to admit. Nice work.