It looks like I'm a little late to the party, but I played the demo just now and I quite enjoyed it. So I guess I'll say some stuff about it.
1) The Nitori player is really great. She's unique but not hard to use.
2) The background is really great too. A lot of 2d backgrounds look really out of place, but this just seems to fit perfectly. I didn't even notice it was 2d at first. It looks really nice, good job with it.
3) The stage design is great. I love the trails of fairies that fly across the screen when you defeat the lead fairy, very creative. This is the sort of inviting stage design that makes you want to see what's going to come next.
4) Tunnel vision is a good spell, but it seems like I get hit by cheap shots a lot. It's a bit of a problem that the green and blue bullets get hidden behind the red bullets, although that's kind of inevitable with danmakufu. The fact that the blue and green bullets move in such strange directions, as well as the fact that it's the hardest card in the stage, kind of accentuates the problem, though.
5) I'm not really sure how the name of Optical Illusion relates to the danmaku, but whatever I guess. It's a good spell, anyways. I really love the use of those glowing ball bullets, it gives the impression that they're lanterns spinning around or something.
6) Broken Lantern seems pretty forced to me. Spelling 何 in danmaku seems like something from a joke script, not an actual full game. I'm sure other people have different opinions, but it left a bad impression on me.
7) I realize that this came out before DDC, but Walking Backwards with Closed Eyes just seems like a lazy rip-off of Seija's spells, without any of the nice effects. You should at least add in some effects, even just a circle around the player or something.
Anyways, the previews of things to come look quite exciting as well. I'm looking forward to the next version.