Yes, this is the best time to cover these, since Stage 6 Yuuka's
animation state is reset in a variety of the boss phase end functions…
Part of P0086, funded by [Anonymous] and Blue Bolt.
… which allows a split into first rendering the top part of every
pellet, then the bottom part. This way, the game only needs two
grcg_setcolor() calls for any number of pellets.
Part of P0085, funded by -Tom-.
Since they're determined by the order of sprites in a .BFT file,
they're best auto-generated by an enum as much as possible.
Part of P0074, funded by Myles.