So the nameless hero is actually a part of the Reaper Squadron, and part II is an accounting of the situation from outside of the group. I am still working out a way to re-write part one that makes more sense in that regard.
A few thoughts on Part I. It seems split and could have better cohesion. I think you need to set the stage with a better narrative initially and then zoom in on the B.R.O. force.
The year is 2141.
-Go into straight narrative, talk about humanity, the state of earth, the invasion. Avoid pronouns (We, I, me) in this part and avoid words like our too. Say things like "Earth has been at peace for over a century." and "Humanity's search for intelligent life has been unfruitful, even with our bounding leaps in technology, extending our ability to scan planets in neighboring galaxies."
This will paint a strong picture that earth and humanity are together and one entity, a focal point of the story. It sets the stage for Earth vs. The Invaders.
Los Angeles Outskirts - 1400 hours
-Make this like a diary entry/confession of the Reaper Squadron soldier. For the first sentence, I'd suggest you to use this paragraph, "In my 22 years of military service, I never thought there would come a day when I would be helpless to protect the people of this planet. For now, there is no time to reflect on the matter. We must try to re-establish communications with the remaining coalition forces." Then build on that with heavy pronoun use--I (the soldier), we, us, our (humans, B.R.O., the government)--as the hero tells his story and where he is at now. This will make zoom in on the front lines of the conflict of the Humans vs. Invaders that was painted in the starting narrative.
Part II: It seems like you're going for straight narrative here again which works as you're building suspense by teasing that Reaper agents are out there. This being the case, you need to decide if you're telling the story from a human's point of view, or just narrating it. If you're not telling if from a human's point of view, I'd edit the "Our own defenses turned against us" into "Humanity's defenses turned against them". Go through and replace the "our"s and "us"es with nouns and see how it changes the feel of the story.
tl;dr - I think if you did some organizational tweaking to Part I it would set the stage better. Part II is very solid, I'd change over the pronouns and tell the story from a non-human POV for maximum impact.
Looking forward to Part III, I hope there is more enemy stuff. The drone has a heavy H.R. Giger feel, so choice.