Having loved All The Birds In The Sky, I was dismayed by this follow-up: not because it's serious and dark where Birds is light-hearted and, um, also dark, but because its exposition is lumbering and its characters are cartoonish. A key early moment, where our main protagonist encounters an alien many generations after first contact and instantly intuits something no one has ever grasped about this species, is a fair representative of Charlie Jane Anders' approach throughout the book: for this character to have the world-changing arc the book needs her to have, this thing needs to happen, and so it does. It isn't plausible for the character, it consigns all previous human civilisation to braindead barbarity in a way which while sadly plausible remains wildly underexamined for the rest of the book, and it creates the sense that anything at all may happen at any moment in this story. We're going where the plot diagram requires.
Again: I adored All the Birds in the Sky. It felt integral and well conceived and full of insight. This feels like a first draft. If it had been the book that introduced me to this author, I would have given up on her on the spot.