Whoa. This title theme... I stayed at the title screen for the entirety of the theme, I got goosebumps all this time listening to it.
Anyway, the graphics are quite impressive too: in-battle sprites, and bullet patterns even. The gameplay is a bit too leaning towards the easy side but that's because it's the first arc so it's understandable. I really like the battle mechanics, especially the danmaku costs/recharge and their special effects. I see potential in this.
The story is really good too. I really like how a second arc ("exploring and knowing Gensokyo) )has begun in the middle of the first arc ("helplessly running away"). And then the demo ends right after the first arc finishes, when the protagonist has gained determination and sets out to find a way to go back home. It was a perfect setup of a story hook.
In short I enjoyed very bit of this game, and I am looking forward to the full version.