The product description for this book wasn't honest, and that kind of ticks me off. The way it's listed on Amazon, it looks like you're going to get a novella-length story written by Stephen King and his son Joe Hill. There is no mention of the fact that the last 25% of the eBook's length is taken up by teaser chapters from King and Hill's forthcoming novels (at the time), Doctor Sleep and NOS4A2, respectively. When the advertisements stuffed into the back amount for 25% of the page count, it just seems to me like you're paying to be pitched to. Also, not knowing from the get-go that the last 25% of the book is ad space, you get a false sense of how long the story is going to be. It really kind of fucks with the story's rhythm and flow. Yes, you can open up the Look Inside sample and see the teasers listed in the TOC for this book, but who does that when purchasing something written by Stephen King? I'd say about 1% of the potential buyers. Also, when you've downloaded (side-loaded, or whatever) the book to your Kindle and open that puppy up, you are taken to the beginning of the book to start reading. It takes a special effort to look at the table of contents. And why exactly would you look at the table of contents before you start reading what you think is a novella?
Oh, wait, what about the story, the (at most) novelette, In the Tall Grass? It was pretty good. It started out genuinely scary and got rather disturbing and disgusting as it went along. All very good for a horror story. BUT the ending was so goofy and filled with dopey, unrealistic characters, and, worst of all, it was redundant. We already knew what kind of story this was pretty early on. We didn't need a giant, tacky neon sign at the end to spell it all out for us.
Get it from your local library's digital collection or wait for a price break.