I can honestly say that I have not been quite so disappointed in a book in a very long time. I am a fan of Joe Hill. I love his writing. Heck, I even own my very own copy of Heart Shaped Box. I could not wait to get my hands on horns. It only took me to the first flashback to regret that feeling.
That is the main problem with the book. The story goes through one flashback after another. It is very hard for the reader to keep up with what is actually happening in the moment and what is a memory. Another sticking point, is that some of the flashbacks seem more like fillers than anything else. Most do absolutely nothing to further the story. Even the side characters have a flashback in the book, it is all time consuming, disjointed, and quite jarring to the pace of the book. More than once, I thought to myself, "Oh, just get on with it." That is never a good sign.
The other problem I have with the book is the main character himself. When Igg dicovers his power, he basically does nothing with it, other than talk to snakes - which, in the end do not help him at all- and scare away some teenagers. He hangs around in the woods all book long, for the most part, and gets his butt handed to him at least three times by the baddies. It just makes no sense. Another thing that makes no sense is the ending, the reader is left having no ideal what actually happened to Igg. Even when he finally does beat his arch-rival it is without any fanfare. The source and scope of his power changes too much in the story as well. Some characters who were effected in the beginning were not in the end. Some folks who saw the horns at one point seemed almost like they couldn't at other times. It is a little tough to explain without giving away the plot. But needless to say, by the end, the reader has no ideal what Igg can or can't do. That in itself pretty much ruins the whole book. I give it 2 stars - at best.