How do I do Spacesphere "Earth in a Pot" (Eirin's midboss spell)? I've seen people circling around the outside and destroying familiars but I can't figure out how to do it on more than 1/30 attempts :<
Some human characters have easier time destroying familiars than others. I can destroy them all with Marisa and most of them with Youmu, but less than half of them with Reimu or Sakuya. The trick is that familiars themselves are harmless, so you can go through them freely. They can also be harmed all the time, so you should shoot them as much as you can from when Eirin spawns them and until they form the circle. Hopefully, some will be damaged or destroyed by then. After that, try destroying them one by one and keep remaining ones in one group for easier dodging when they start shooting. This is where them being harmless is important, since you can position yourself inside them so that all bullets hit one familiar (shotgunning it's called, I think). Especially useful with destroying ones below you, since you can go low enough to harm them with your shots but high enough so as not to get hit with their bullets.
Another trick is that the circle is centered on where you are when Eirin starts spawning familiars, except it doesn't go outside the screen. So you can hug the bottom to have easier time, destroying lower familiars first and cutting on bullets from below when they start spinning out.
As for actually dodging, it's a sort of a streaming in a circle, but with a bit of randomization, so quite a bit of reading ability is still needed.