This book suffers from the middle-book blues in which the second book of a trilogy is neither here nor there. The first book in the trilogy, Annihilation, was told from the perspective of an expedition member, and the sense of exploring a new environment was exhilarating. This book shifts perspective to that of an agency director for the government's science facility that sent all those expeditions.
Narratively the sense of discovery is actually more natural in this second book, because there's less "hypnosis made me forget" artificial suspense enhancement, and some of the descriptions of the facility are creepy enough to evoke the Dharma Initiative from LOST in the best moments. But it ultimately doesn't pay off or answer enough questions to justify the time spent in telling it, and feels like a shaggy dog story. Some narrative jumps make the story harder to follow without building suspense, and the really weird reveals are mostly in the first half, while the second half seems more predictable. It might pay off in the third book, but reading it seems more like a duty than a pleasure at the moment. Don't get me wrong, I will read it, and the atmosphere itself almost makes this second book worthwhile -- I just think it'll be better if I keep my expectations low.