At last, I got a change to try the game (installed windows just for that) at least at easy with ~52 FPS.
I liked preview videos of the game and I wasn't disappointed with actual game. Very nice music, game mechanics, bosses, and quite good patterns/spellcards. Even if it's not an official game, it really looks like one. Ura mode (is it the right name?) is a nice addition but difficult as hell, even in easy. The only noticeable drawback is the balance, it really should be improved. Otherwise, it's a good game. Looking forward to try Extra when it will be added and I get my GPU card back.
Mesarthim, Lady Mima, I have a feeling that your problem is that you downloaded danmakufu separately, not using the one which was provided with the game (at least, I see that Lady Mima runs the game from not native folder). It's possible that you use incompatible version (even if it's newer). And yeah, you need to be sure that you use bugfix (though I have no idea what exactly it fixes).