I didn't find this book scary. I just found it really depressing, a soul-wrenching look into losing a child, and, apparently, a morbid what if for Stephen King. 
 Not to say that I didn't enjoy it, because I did. It is a very well-written and emotional book. But I just did not think that it was scary. That seems to be a problem I have with all the Stephen King books I've read so far. They just don't terrify me like they seem to do to everyone else. Perhaps I've been too desensitized, but I have read stories that spooked me before. 
 Part of this book feels like an exploration/ discovery of just how far a person (or King) would go in the midst of grief. Also, it feels partly like a warning not to mess with things you don't understand. I read somewhere (view spoiler)[(probs from LitReactor) (hide spoiler)] that someone thought that the theme of this book was "dead is better," but I'm not so sure I believe that. I believe it's more of that death is awful, a cruel ripple effect that can destroy the lives of loved ones, and that moving on is not only healthy, but essential to our survival. Death is a constant, cruel reality, it's not good, but it's not a permanent aspect of life, and you can't get around it and bad things happen if you try. 
 All in all, I enjoyed this book for what it was, a heart filled way to come to grips with the reality of death and the very real possibility of losing a dear loved one. But, despite being horror, it was just not that scary. 
 I have a feeling King was trying to make the big-bad wendigo terrifying, but the problem I had with that is that the description alone renders it less scary. A vital aspect of fear is the unknown. The wendigo in Pet Sematary just looked ridiculous in my mind. Look up Algernon Blackwood's novella, The Wendigo, to see what I mean. That story did terror of the unknown right. Despite the fact that Blackwood's wendigo doesn't do as many horrible things as King's, it's much more frightening. Now that's a truly terrifying tale.