My first thought after seeing the movie: It wasn't as different from the book as I thought it would be. It actually was quite similar with some noticeable differences but nothing too big.
The movie didn't have President Armelio in it, which kind of bummed me out, only because I was expecting the whole 'I will crush you in spades' thing. Also, they didn't play cards, but table tennis. Which was fine with me because I personally really like table tennis no matter how much I suck at it!
In the movie, they ended up sneaking out twice in nurse's uniforms which never happened in the book. I'm not sure if I liked this addition or not. I still can't decide. They also had a pizza party at the end instead of a movie. I think I liked this better in the movie just because they had talked about having a pizza party at the beginning, so it seems fitting to have one at the end as a kind of resolution of sorts. Plus, everyone got to see Muqtada come out of the room finally, which was awesome!
The romance between Craig and Noelle was pretty similar to that of the book. There were some minor things, but that's it. I kind of wish they would have put the whole Noelle, emotional scene in the movie, but that's okay.
Overall, I really liked the movie and I loved the book!