FANTASTIC - one of the best casual games I have seen in a few years.
Minor annoyances: control layout is not very intuitive. Music gets really annoying after a while. Maybe just drop the different instruments in and out every so often for more variation. Needs a health bar or something, it's not obvious when you're doing badly.I was pretty surprised the first time I died.
It looks great - really unique feeling. And delighted to see that it's the latest iteration of a project that began in 2004 (the menu links to the github). Well done!