This game is really cute! After making a music/rhythm game, I am really appreciative of the attention to sound design in this game - love the whistling track and the switch between the two tracks is great.
I think the theme might come through a bit stronger if the hole was square shaped when accepting circles instead of just being round the whole time, but not a big deal. There's also a huge jump in difficulty between level 1 and level 2 which I enjoyed but was a bit jarring.
My favorite part was using the crazy physics to launch shapes I wasn't holding into the hole. Nice work!