I had a ton of fun with this. The 'story within a story' style combined with the eerie writing and continuously mounting tension among the characters - within both stories - had me at the edge of my seat and I couldn't put it down (I actually read this in one sitting, so quite literally). While the culprit was in my small group of guesses, the twists and turns that story took were engaging and I was still quite happy with the outcome. 

The 'meta' portion of the story - WOW. I'd love to have a whole book of that story. 'Real' Leo sure was...something to say the least. One thing I wish we got a little more of was the 'story' Leo - what was his purpose, who was he, what did the ending mean? The open-endedness of the story did add to the eeriness, so I can't be too upset on the lack of information.