Awesome entry. I love the amount of juice the game has, the whole thing's visual style feels very Vlambeer inspired. I also really enjoyed the small detail of drones that just fired moving to the back of the flock.
I guess my only "real" criticism (more of a nitpick, really) is that I would've liked to be able to visually distinguish the player from everything else more easily. I found that when the camera really started to shake around and there was stuff flying everything, I had no idea where the main character was, aside from inside of this mass of drones, just so there was some visual center my eyes could come back to more quickly. Not really a huge deal though.
But yeah, great art, great game-feel, good audio, and nice simple gameplay with a neat visual catch with the flocking behavior. Just a really good entry.