So, I played up to the point of killing one of the bosses (The Earth, I believe?), and I think my favorite feature is how the powerups layer on top of each other. It makes you feel really powerful to have all of them at once, however rare that is. I like the different types of enemies too, they cover a nice range of attack patterns.
My major complaint is that, for me anyway, its difficult to touch the powerups - between my high move speed, my tiny hit box, and the equally small powerups, it usually takes several passes just to get one.
Other observations: I was constantly wishing for a way to heal myself (even just a tiny bit), I would appreciate it if the menu when I die would also include the option to replay the same level (instead of having to select it in the map again), and finally, I don't see how the story ties into anything (it sets things up as some kind of Orwellian dystopia and eliminating dissenters, but nothing beyond that opening narrative ties into that theme, it just feels like a normal top-down shooter).