I loved the writing in this. It had some personality and a nice little arc. I'm not too familiar with Kyouko and Mystia, but they were cool characters and their relationship was fun to watch. Echoing ghostguts's thoughts, I was pleasantly surprised by how gay it was. Though, I think the stint of drama before the epilogue could've been better led-up-to. Maybe it was and I just didn't notice the foreshadowing, but I think one more scene showcasing Mystia favoring the band over her relationship wtih Kyouko would help.
As a side note, I love it when Touhous interact to outside world technology with curiosity and wonder. For some reason, stuff like this always gets me to smile--
I had found a few issues with the textbox. First off is that pressing spacebar instantly skips text even if it's still scrolling-- it should probably just made that text scroll instantly, so pressing spacebar again moves you on to the next line. Putting the narrator's name at the start of narration seems kinda unnecessary, and at first it got me confused on what was dialogue and what was narration. Also, the last line of text in any given textbox always scrolls more slowly than the first-- is that intentional?
Also, this looks weird. 
As for the songs, I think there should be more customizability with the controls, as well as a visual indication of a note having been hit (like the note lighting up). Also, the first song had a weirdly long silence at the end. And then, like Kiroko mentioned... some songs were mostly loud static. For me it was the song before and after the fourth rhythm section.
Also...
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In short, 'twas a rockin' story with a lot of technical issues.