I watched the movie a couple of days after finishing the book. Books are always better than movies, but in this case the book its a million times better, the movie just doesn't do it justice.
I really missed a lot of things such as Clemensia with the snake attack (which didnt reach my expectations)and the aftermath of it, or the way Lucy Gray wins the Games.
The casting I don't think it's so good, the best one is Viola Davis as Dr Gaunt. Snow is portrayed ok, but it misses a lof inner moral fight and the high anxiety it causes him that he might get caught. I also didn't see him really falling for Lucy Gray as I would have liked to see.
All in all I was disappointed with the movie, I expected better.