Let's go, a shmup! I certainly like it, though I did get frustrated at the third pattern - there were just too many things for me to track at once, and my micrododging sucks (I am much better at macrododging patterns). I feel like getting rid of the base shot would work better, since it only deals meaningful damage in the first phase and it kinda prevents you from learning about how the aura works there. I would also love to see the boss indicator at the bottom of the screen, it is genuinely really helpful in touhou-style shmups. Some weak homing on the reflected metal projectiles would be also nice, so that you wouldn't be forced to occupy the same 20% of horizontal space as Patchouli, which is certainly an issue for streaming patterns.
Don't be discouraged by my list of criticisms - I did very much like the concept, and these things I said are pretty much just some minor adjustments. Hell, you could even take it further and make a full-blown shmup out of this.