Good game with a nice aesthetic to it. The take off animation is well done too and I like the way you represented the various steps of the progression.
The collisions are a bit off and it would have been nice a little more feedback, bounce or noise or some visible invul effect or something. The collision with the feathers makes it a little weird too.
The balance of the upgrades seems strange but I couldn't reset my progression so I can't check, it is expected in a game jam though :)
However it was fun to play and I'm glad I made that kiwi fly :)