I was a bit scared at first to pick up this book because I'm a chicken and normally don't do horror stories. But even though it was quite creepy and gory at times, it was Supernatural level, so if you can do Supernatural you don't have to be scared to read this book. 
 Actually, the whole book gives off a bit of Supernatural vibe, the main character, Cas, reminds me in some ways of Dean. All the characters, including Anna, Thomas and Carmel are fantastic. 
 The story is well-plotted and fast-paced, there are many scenes where you just can't put the book down. 
 The goodreads rating is well-deserved and everyone including the easily-scared types like me should read this book.