Super cool game!
I love the overall aesthetic, and the bite attack is really awesome. The bullets do feel a little fast for the first level - it almost feels like a midgame or lategame right off the bat. And the laser seems to use all of your ammo instead of just one at a time, which is a little frustrating when I'm trying to save it for the boss. But, I adore that the microbes change color each level; I think that's a really, really cool detail!!
I think it would be really cool to see some sort of classic power-up system to bring your microbe from a little wimpy shot at the beginning all the way to the supercannon (or beyond) that the demo gives you. But I'm super excited to see how the game develops!