This one is a bit strange, not really a game so much as a trainer for different bullet hell scenarios. You can find the link to the download page nearly at the bottom of the developers page. I am not sure if this is a kenta cho production or not, but it is built using his bulletML package.
Once you get to the download page, you may find that you need some instructing as to where to get the file. Luckily, the2bears has posted a guide to downloading from the vector.co.jp pages.
Once you manage to get it downloaded, there is a link in the english readme file to a forum post that explains the basic play mechanics. Enjoy!
P.S. you can download a windows version at that same first link.