I learned way more about computer graphics here than I expected. Kudos to the author.
One nit: the picture that the author called "The sun" is actually Eirin [0] looking at the moon. In that scene [1] she's reaching for the moon, where she was exiled from, only to hesitate and retract the hand. In the next scene, Kaguya [2] also reaches for the moon, but does not hesitate. I'm not sure what the symbolism here was supposed to mean, as according to Touhou wiki it was Eirin's plan to steal the moon.
[0] https://en.touhouwiki.net/wiki/Eirin_Yagokoro
You may have misread, the wiki says her plan was to 'seal', not 'steal' the passageway between Earth (or Gensokyo) and the Moon. Eirin deliberately chose to break her connection to the Moon in order to protect Kaguya.
> One nit: the picture that the author called "The sun" is actually Eirin [0] looking at the moon.
I always think 'the sun' when I see it because of this goofy video: https://www.youtube.com/watch?v=ReblZ7o7lu4