We had to re-implement the upgrades relatively close to the deadlines, so we didn't get much balance time on the upgrades. We also played with the speed upgrade for the side-to-side movement, so I think we just needed a little more time to tweak things. It definitely can start to fight against you.
We also did adjust the tiles so you couldn't get stuck going up at high speeds, that was also a thing :P
Thanks so much for playing!