I started out with some high-resolution artwork, but when I imported into the game, I realized that the high pixels required a higher frame rate than the low-pixel to watch the flow, so I eventually gave up
It's true, this structure uses 3-12 frames and can get complicated! If you're using 16x16, I encourage you to start at 32x32; the sky's the limit. Good luck with your projects, and I'm glad you liked the demon girls!