Well, that was a trip! 
 The Good Stuff 
 Jason is a great protagonist. He had a personality, he had attitude, he had the brains to figure things out. I enjoyed following his journey! I also felt his extreme fear and sadness when everything in his world takes a turn for the worst. 
 The plot is fast-paced and it rarely lingers for too long on scenes. The action is immediate and you're left sitting there completely out of breath. The story is complex and strange, but really engaging. I listened to the audiobook, so what some people may be complaining about as far as Crouch's writing style (apparently he uses really short paragraphs and two word sentences) came across as very conversational when listening to the narrator. 
 The Not-So-Good Stuff 
 Like I said, the plot is fast-paced and entertaining. HOWEVER (and I think this is quite a large however) it was super, super confusing by the end. Sorry guys, but I have a big spoiler here: (view spoiler)[ I still can't wrap my head around why and how there are so many Jason's by the end of it. I mean, they are still the same Jason that we followed into the box, but somehow he multiplied and split off in different directions off-screen, which in turn creates more and more Jasons...and now I am giving myself a headache. It just left me feeling confused and muddled. I don't like being left feeling confused and muddled at the end of a book. (hide spoiler)] 
 Look, I don't actually like Science Fiction. So the fact that I was entertained by this book at all is pretty cool. But when phrases like "developed a hypothesis" or "protons smashing together" are casually thrown into the narration over and over again, I get bored. I get frustrated, and I revert back to my sixth-grade self that is embarrassed in front of her classmates because she doesn't understand science and math like the rest of them... We get it Jason, you are a scientist. I am not, so I can't really understand everything you're saying at this point. 
 Overall 
 This is a really good book. I really liked it. I thought the plot and the premise were exciting and enjoyable. I liked the main character when he wasn't speaking in the foreign language of science. I also thought the ending (bit of a cliffhanger, be warned) was pretty good! I would've liked to have seen a bit more closure, to be honest. But, overall, this is a really solid read.