I'm okay with this book. I like the zombie approach; though for my taste, I wanted more creepiness around their "experiments" of the Under-sixties. Maybe I didn't want Wren to be so... Wren. I don't know, I wanted her to be more 178 (?) Maybe it's because it was her point of view. But come on, how can ALL reboots be updated as beautiful? Is that a defensive mechanism? Oh hell, then I am up for it, no? Don't quite understand that. Is it a cosmetic disease? Moreover, I didn't like how Callum and Wren get all lovely dovey, a typical YA first-sight love. I wanted it to be more believable... (or maybe I am just annoyed because I wanted a more sexy scene in the HARC showers) 
 And not to sound weird, but I wanted people to exclaim: "how does a 178 like a 22?" Widening more that division between under-sixties and upper ones. 
 Unexpectedly enough, I liked the scene with Callum's parents. I was expecting it to be extra-cheesy, but glad it wasn't. As far as I can tell, I liked this book because it is cheesy, but not too cheesy. Nonetheless, I wished Wren wasn't such a Mary Sue. I know she can kick ass, but it feels too easy. The things she does shouldn't be as easy, lots of things can go wrong! That would have made all more believable.