Wow, your comment really made my day. It is such a great feeling to see the vast majority of my initial assumptions and imaginations fully realized by another soul. I mean, doing crazy high-speed low passes in the forest, shuttling back and forth through the village, and circling the SDM is exactly what I am addicted to these days.
Your guess about Marisa's turning is actually pretty precise. The clear description you came up with can immediately help the design of a better tutorial. I really appreciate that.
Reimu's control indeed requires some workaround. I am currently working on a smarter system, hopefully, that will solve the existing problems (and not introduce more new ones).