One really cool writing technique in this book is the way Lunetta plays with verb tenses. Sure, verb tenses don't sound all that exciting in the abstract, but she uses them to great effect to move back and forth between the present, the future, and the past, which allows her to create a greater sense of mystery as to what's gone on with Amy than if Lunetta simply told the story chronologically. So she starts in the present for Part I, and then Parts II and III play around with future and past, having jumped several months forward in time from Part I.
While this book is billed as Book 1 in a series, and the ending certainly leaves plenty of issues open to explore, it also works as a stand-alone book with the heroine's journey nicely rounded off at the end, so readers won't be left hanging. While the book may be off-putting because the hardcover at least is pretty bulky, it's an engaging read that you can get through in a day or two - younger readers will take a little longer, but it's not challenging in terms of dense prose. So don't be put off by length. An entertaining, thought-provoking dystopian read.