All around a very impressive demo, everything I've seen is finely polished and the game plays very well.
However I have to admit I do have some trouble noticing where my character is, despite dimming the background and making the bullets pink. I think they would read better if they were the brightest color they are when strobing.
Aside from that, I've found speeding up to be kinda counter intuitive as someone who's only experience with shmups are Touhou and Mushihimesama, you get used to it after a while but I'm still not too hot on that choice. And there are some enemies which you can't really shoot unless you absolutely master the movement, which kinda feel annoying, but aren't that awful.