I like this Bullet Hell. Although the bosses' patterns were rather generic, it became a fun challenge by the combining of two bosses at the same time.
While somewhat challenging, it wasn't too hard. I liked how the upgrades gave you some freedom to test new styles.
The only things I can complain about are the use of 3D backgrounds with a 2D surface - I always think that the styles clash too much - and the music. It felt kind of repetitive and generally hard to listen to. There should have been a possibility to turn the music off but keep the sound effects, since I liked the voice.