Unique, fun, but laggy
This is probably the most unique rhythm game I've played in a while (I've never played DJ Max Technika, though). And the fact that it's on flash brings up a few differing pros and cons.
For one, some of the charts with movies in the background (Cirno's Perfect Math Class, Isabel) lag up Flash a bit. And I couldn't help but notice that some of the notes are slightly off-timing. But then again, all of this is to be expected in a Flash game. You could avoid it by crippling the game in some ways, but I can live with it (as can others, I guess).
I've been playing various rhythm games ranging from Guitar Hero and Rock Band through to ITG and StepMania (pad and no pad). This one uses a mouse. Simple and effective. Imagine it ported to iPad or played through the browser of an Android tablet... *flatten*
Song choice is pretty awesome too. I HAD NO CLUE YOU'D PUT IN YOUR OWN SONGS KOIZUMI =w=
And it's damn fun to play! I've got my hand in a totally alien position hitting notes, but you've chosen the right keys to use (space bar seems a bit iffy, maybe replace with Alt key?)
9/10. The only problems are the unavoidable lag and looks. They seem kinda Windows XP-ish and jittery. But then again, flash. :\