This is one of those rare books that is nearly impossible to categorize, and refuses to fit into any particular genre. There are strong elements of fantasy and horror throughout, but it never quite lands in any one place long enough to be easily defined. It contains plenty of dark humor and absurdity (which reminded me of Tom Robbins or Christopher Moore), as well as creepy, intricate, and creative world building (which reminded me of Neil Gaiman). Picture, if you will, American Gods except with a black sense of humor, deeper mythological roots, and a dash of ultra violence.
One of the biggest strengths of the book, in my opinion, is the world that Hawkins has created. There's an amazingly robust mythology within this book, that is so bizarre it has the ring of truth to it. It has that rich weirdness that only the very old myths seem to capture. I've never read a modern book that had such well realized and original mythology. Very cool stuff, and it's very central to the story itself, not just tacked on for scenery.
The plot is such that anything I say would give too much away. The book itself is a jigsaw puzzle that only comes into focus when the very last piece falls into place. It's one of those rare reads where I had no idea what was going on through most of the book, and yet I never felt lost nor frustrated. You just sort of get swept up in the events, much like one of the main characters, Steve, and wait to see where it all takes you.
Characters. Ah yes. They are weird, and varied, and interesting, and well crafted. Really striking and memorable. All of them sympathetic, even the worst of the villains. And yet I didn't particularly empathize with any of them, nor care what happened to them. My investment was very low, which is why I didn't rate this book higher (I read for character). I was in the minority within my book club on that particular judgement however, so you may have a very different experience. I'm not sure what was missing for me, only that I had a lack of strong connection.
In short, if you've been looking for something in a similar vein to American Gods, this might be it. If you're looking for something irreverent, fresh, and creative, with unique world building and a cast of complicated people, this one is truly one of a kind.