This is the kind of book that really gets into worldbuilding, especially in the earlier parts. The reader is introduced to all sorts of weird concepts in the universe, and even if the earlier introductions feel like a bit of a dump, they are smooth—the setting is inventive with its space magic empire, but shows that it is a space magic empire from the get go. The overall concept of the book's universe is, by itself, also captivating.
There are ways to do vast, dystopian interstellar empires well, and there are ways to do them badly. Fortunately, Ninefox Gambit does them well. The story is pretty dark, and the setting is grim, but it doesn't feel gratuitous. Horrible things do happen to characters, but they happen to characters, instead of merely as an arbitrary background violence that punctuates the point. The story feels like it is, appropriately enough, about how people exist within the machineries of empire.