Entertaining and thrilling for the most part, but it lacked character development.
Because this was part two of three, there were hints but no real answers to what was going on, making it confusing at times.
The actions of the characters didn't seem entirely logical either; they were told at the start that what they were about to experience may or may not be real, but they never questioned any of it - although in their defence, they were too busy trying to survive.
The secondary characters didn't have any real development or story arc, and I get the impression the ones that survived to the end were the same as the ones that left The Glade. Nothing about them seemed to alter, and as a result, they were two dimensional and difficult to empathise with.
One review I read commented that Dashner uses nouns for his Big Ideas - The Glade, The Flare, The Trials. I noticed it as well, but can't complain about it too much, since I do it in my writing!
It also got quite repetitive the number of times Thomas was knocked out to move the plot forward.
Despite the shortcomings, I enjoyed it more than The Maze Runner (soon to be a major motion picture) and I'm starting on Book Three today (The Death Cure) to see how it all plays out.