The setup is effective. The school's designs are vicious and sinister right from day one. The students are functionally prisoners, scrambling to stay alive and figure out where they are, why they're there, what's planned for them, and how to escape it. The dialogue is sharp and the time- and location- jumps in the story are well organized.
My only real complaint is that it keeps piling up more and more mysteries and questions and weirdnesses without wrapping anything up. I'm not at all convinced that the author knows how it all will tie together (See the TV show "Lost").