Saw the movie first, so the various reveals that crop up throughout the story were not hidden to me. They didn't make the film any better, and the same could be said of the book.

The biggest question in my mind is whether to tag the narrator as unreliable. The entire story is told from her perspective, and bounces around as she remembers various parts to her narrative. Unfortunately it is pretty obvious this is Ishiguro's method for hiding some things until revealed later.

It works as a story, and either the children are all oblivious to their situation or the author didn't want to write about the conflict. Either way, it's a depressing book which was just "okay".