Nice game! The mechanics are pretty interesting, as you're constantly switching between trying to avoid the trees and then wanting to hit them once you have a power up. It's a quick and satisfying game loop that makes it easy to keep playing! Also, I know everyone has already mentioned this, but the sound effects really bring everything together. They're so cute!
One thing I might improve is the visibility of the +(dragon) icon that appears when you fill up the Next Time Bonus. It gets lost in all the "Wee!" and "Ouch!" labels and it took me quite a while to notice it. Maybe it could go beside the dragon bar on the left, or just in the middle of the screen?
Otherwise, great job!