Considering how short this was it packed a huge punch.  Technically this was extremely well written as well as being a great story plot and concept.  The world building and history was brilliant, using world history and expanding on it in a horror/supernatural way.  The characters were so fleshed out and realistic, with real depth of emotions and back story.  This book had a lot to say and it did it elegantly, violently and with nuance.  Amazing!!