The game keeps wiping progress. Absolutely ridiculous.
Also, in the boss levels in particular, there is a problem with the size of the boss as compared to the playing area — which causes a loss of control (and almost inevitably a loss of life) when the cursor strays beyond the bounds of the playing area.
The whole medal system seems to be somewhat off, based simply on some sort of point bands rather than your actual rank in the World Cup? Going into the final match, I was in second place, behind by one point. I came equal first in the final match, but beat the overall leader by five points. That is to say, logically there is no possible way I could not then be the overall number one, but I only received a silver medal.