I liked this one overall, although it definitely had a few flaws it was a nice short and sweet experience.
The art deserves praise. It's cute and colourful, and the frame reminds me of the Super Game Boy of all things. The choice of bright, bold colours and big solid areas might be called uninspired but I really liked it here.
I like the music, I like some of the sound effects, but the enemy death sound is really grating. I think this is intentional, but it becomes unpleasant to hear pretty quickly.
The rhythm game elements would have been great if they worked, but for whatever reason the metronome sound just didn't match up to what the game thought the beat was and I ended up just randomly mashing the fire button.
The pacing and difficulty curve is really odd, to say the least. The first few minutes of the game are very sparse, frankly dull with the repeating background, and don't throw a lot of enemies or interesting patterns at you. I almost quit because I wasn't sure the game was actually progressing or if it was just going to go on like this forever. It also feels a lot more like a western shmup than a danmaku at that point, though not a great one.
Then, suddenly, it goes full bullet hell, throws a ton of enemies with insane bullet spam at you. I suck at bullet hells and generally avoid them, but this was definitely a step up over the dull beginning, with some interesting patterns and intense action. At this point we're pretty close to the end of the game, though, and the boss came up a lot more suddenly than I expected. The boss was interesting, though probably too easy for bullet hell veterans I thought it was well balanced.