incredibly stressful in the same way wario ware is stressful, which is a good thing. if the game levels were longer, i don't think i would have liked it, but the fact that its so short, and every time you fail, you were so close, makes it that much more satisfying to win. I like the idea of the switching mechanic, but there isn't any incentive not to use it, or to switch it back, since switching makes the track longer and therefore gives you more time to repair the track ahead.
The art is really nice and its overall a great submission!