Let me start with the positive: I loved the setting. The author really nailed the atmosphere of Appalachia Kentucky. Also, Owen, Levi, and Cassie were absolutely fantastic characters. Also, the premise of a time flux taking people backwards through time was really cool. In fact, the first half of the book was breathtakingly good. Exciting and mysterious, if a little violent.
But, then, out of left field, a supernatural element was thrown into the book. The story went from cool time travel science fiction to weird horror genre. Without revealing too much of the plot, a mythological god with regenerative powers begins stalking and skinning people. The entire tone of the book completely changes.
My son and I were listening to it on a road trip and we both commented about the disappointment of this twist. The second half of the book was completely different, as the time travel plot diminished and the monster story took over.
The author can really bring a setting to life, and I enjoy his style of writing immensely. But, at least in this case, the change in tone and genre halfway through the book was frustrating to this listener.