Thanks!
Difficulty is definitely first on my list of things to address in a post-jam patch. Depending on how much time I still want to devote to this, I'm considering making it so that the difficulty option doesn't just globally affect the speed of the wheels by a set multiplier the way it does now, but also affects things like the target zone width and perhaps even adds entirely new target zones for the multiple wheel levels to make them easier to manage on the lower difficulty levels.