If you are someone like me, who is bad at shmups but enjoys them all the same, I highly recommend this game. There's a good range of difficulty settings that offer enough challenge so that it never gets boring-- even Easy can get frenetic. Playing multiple runs levels up your overall ranking, which in turn gives you points which can be assigned to various optional perks, from weapon upgrades to extra lives and continues. Not only will you get better with each run, but the game can become a little bit easier with future ones, if you wish.
On top of that, the music and graphics are great, the bullet patterns are intricate and gorgeous, and the shooting and controls simply feel right. I do wish that there were separate achievements for the different difficulty settings when beating stages, but that's my only real complaint. Overall, this feels like a game that was designed by someone with a lot of love and respect for danmaku shmups, and is one that casual players should be able to enjoy as well.