While I thought it was an overall enjoyable read, the plot was heavily borrowed from other sources. Christopher Paolini is a gamer, and for anyone that is familiar with Halo, this storyline is a pretty clear copy, with a maybe a little Expanse thrown in at the end. Halo has humans, the Covenant, the Flood, and the Forerunners. This book has humans, the Jellies, the Corrupted, and the Vanished. There's a war between humans and Jellies, eventually the Corrupted show up, and a faction of the Jellies splits to join the humans while they're all fighting the Corrupted. Meanwhile there's Vanished tech throughout, including what is essentially an Expanse-esque protomolecule.
I enjoyed Paolini's earlier work, the Inheritance Cycle, so I really wanted to love this book too but as more and more parallels to Halo showed up I grew to feel it was a mediocre copy. He was criticized for similar plotline plagiarism with the early books of the Inheritance Cycle, and it's unfortunate to see that he didn't learn from those mistakes.