Great beats, great game
Well before I understood that the beat actually controls the attack style, I quickly figured out that a pretty calm intro followed by a brief pause meant the real shit was about to go down. The game and the music deliver perfectly in-sync, and the music is pretty nice original stuff. Lovely upgrade system- all seven of the upgradable stats fit neatly together, though I especially like the rationing of ships. I had to set -2 as a hard limit for myself for how bad I can afford to do in any level, then drive that number down in previous stages after I'd accumulated enough skill and power in order to proceed late-game. I love the difficulty curve as well as how fun it is to go trounce earlier levels that gave me hell when I was half as strong.
I actually thought it was too hard (yet fortunately quite addicting) at first. And it would've been if not for two very important factors/tips for those who've never played the game:
1. Don't shoot for gold with every new level. In fact don't shoot for gold with any new level. You're supposed to get that by going back after you've leveled up enough. Which will occur with the natural flow of the game.
2. YOUR HITBOX IS ONE PIXEL. See the white dot in the middle of each ship you get? That's your hitbox. So long as an object doesn't touch that one pixel, you'll be all right. And you can fly right through the speakers. This only dawned on me during the credits, wherein I figured out I couldn't not take five punches from it if I couldn't slip between the letters.