If you enjoy Touhou Project, you'll definitely enjoy this.

This review is in fact for all 3 games part of the Gundemonium collection pack (Gundemonium Recollection, Gundeadligne and Hitogata Happa). They are great bullet hell doujin games, of course it's not worth a good old CAVE, but their scoring systems are good and save for Happa, easy to get into. They're probably your best choice to make your first steps into the manic shooter genre. And hats off to Rockin' Android, who not only translate these, but fix bugs (there are still updates today !), add features and cool remixed music. I recommend to buy all the stuff they release if you're into it or just curious.

I am a long-time fan of shmups, with renewed vigor after having more recently discovered Touhou. That being said, this is without a doubt the worst example of the genre I have ever had the displeasure of having witnessed. The prominently-posed naked catgirl boss was enough for me. But even if you're into that in your games, rest assured that there is plenty wrong with this game from a gameplay perspective. Your character takes up too much of the screen, so that shots must come at you either in slow-motion or with very tight limits to the patterns that enemies can make. You have a small but unclear hitbox, which is unfortunately imperative to use with some of the spread gaps in attacks. Some hostile radial bursts even have no apparent gap, as though the developer didn't realize he'd made a no-health-bar shmup. It's rather important to use the special abilities at your disposal, which the game made no attempt to explain how to use or how they work.
The ONLY good thing I can say about this game is the ability to co-op. Combined with the ability to aim backwards along with enemies that make use of that mechanic, could lead to good teamwork moments if the game was any good. As is, inviting another person to play is a passive-aggressive way to let them know you hate them enough to suffer along with them so long as they suffer too, but without telling them to their face. Having Reimu as a boss is just insulting, as though this creation has any right to call itself in the same league. GundeadliGne as well as the Gundomonium collection remain the only games I wish Steam would let me fully delete from my library.

Favorite of the collection, has really nice art and faced paced gameplay.

Bullet-Hell action fun. And anime girls. Lots of anime girls...