I really love how you are incorporating spring with the two different worlds in your game! You have created a nice addictive gameplay loop. I also enjoyed the little animation you created when the tree or mushroom is hit!
But unfortunately, the chopping was a bit too finicky. I kept trying to chop and sometimes it would chop and other times nothing would happen. This made for a frustrating experience and so I never quite made it to the end of the game. I think with a bit more polish of the main chopping mechanic would make this game a lot more fun.
The game has a few minor bugs (donating more material than the UFO needs, UFO disappearing on mushroom day, occasional typos) but definitely not bad for a short game jam!