A really solid Touhou-style boss fight, with a cool gimmick. One of my favorite games this jam for sure. The difficulty is just right for a jam game, with the fight overall being notably more accessible than a normal Extra boss, but still with some tricky patterns that I'm not gonna successful dodge any time soon. I'm impressed someone no-missed it.
I also particularly love the slalom non-spells. It's a bit unusual that you have to stay at the same side twice, but it's a welcome change of pace from the usual right-left-right-left rhythm of high movement spells. I thought the survival was nice, but I can see how it becomes RNG hell if you don't use the slow-down. It could probably be a bit shorter to make it less RNG sensitive? And it would have helped slightly to have the bullets from the top be a different color - it was something that occurred to me once I figured out that I should just slowdown myself into a nice gap in the lower bullets and follow them up: the lower ones can basically be ignored at this point as long as you move with the right speed, so having them be the same color adds visual clutter.
Also, for anyone that has problems with the refresh rate being tied to your monitor, you need to turn off vsync.