Normaly I don't like this kind of game...
... because I'm kinda bad at them, but that's beside the point. My gripes are that even at higher levels, the power-ups were still a bit sparse whit how busy the field was, and the delay on chaining from defeated enemies' explosions. The player's timing needs to be pretty precise to get a chain from moving foes, and getting more than a x2 or x3 chain seems to be pure luck.
That being said, I do enjoy this. The simple visuals work quite well for the game, and the trails left on the background feel like a nice touch, and it is nice that your ship has a small pull radius for collecting chromium. Also, a big plus for the levels melding together so easily. All in all, this is pretty solid, though an upgrading system of some fashion (scoopeman's sounds like a fair idea to me) would help keep the player engaged.