I really enjoyed the whimsy of the main  menu and spent longer than I'd like to admit playing around with the balloons there. The transitions into the game were a bit jarring but not out of line with a game jam entry. I really wanted to enjoy the platforming gameplay as much as the menu but I think the space between buildings really held me back. It would likely benefit from a much closer and whimsical level setup. For instance, splatting against a wall when boosting was kind of funny, but it was also pretty much a death sentence since that meant you'd hit the ground. 
Overall a really interesting idea and technically well done.