Very cool premise and I liked the execution. I've seen this categorized as dark fantasy (and it is!), though it has some strong horror elements, as well. There were also moments of surprising tenderness and humor. 
 My only complaint is that it felt a little heavyhanded at times. I also wished in a few cases that Hill had resisted explaining his clever jokes and references a few paragraphs after presenting them (because I did get them!). Still, an enjoyable read.