screwed up physics
The slopes are done all wrong. You can actually go up onto a slope and come to a stop, and you'll just stay there, without pressing any keys, and you won't roll off it. A slope in this game seems to multiply your motion in the down and sideways directions, which is definitely not the same as what a slope should do.
It was also kind of annoying that pressing two keys like up and left does not make me go exactly diagonally along the game board. It makes me drift slightly.