A beautiful little rhythm game. You might be annoyed by the fact that harder difficulties are initially locked, but once you reach them you're in for the ride of your life. Nods in the achievements and the structure of the light story clearly show that this is a game by music lovers to music lovers.
I've played with classical, electronic, and jazz and have gotten great levels out of all of them, with significant variance in the design (the key features being the speed of enemies affected by the tempo and the number of enemies by the volume).
Honestly I was shocked to check the Steam usage stats and see just how few people play this game on a regular basis. I would wholeheartedly recommend it. I would alse recommend the Extra Credits youtube vid on the game-- it was what got me to buy the game in the first place!
If you've already got Beat Hazard or similar, well, the gameplay is somewhat similar (action shooter to music).
The actual area your ship is in is smaller than it seems, and your hitbox is larger than it feels like it should be. The counterpoint to this is that picking up points repairs your ship, and oftentimes you won't die from one hit. Still, the ship size gets annoying, especially with higher enemy densities and higher difficulty settings.
Weapon drops are seemingly by random chance, though if you have enough music this won't be a major issue until the late game, when Furia (rare) weapons become more important. Level 5 standard weapons will get you through, but it's certainly harder. In my experience this wasn't a huge issue, as Furia weapons dropped often enough, but if you're unlucky...
Overall I give this game a Recommended/10.