I was especially pleased that Ender's Game had nothing of that “special effects for special effects sake” sensibility that has marred so many recent films. The special effects completely served the story. In fact, I do not believe this story could have been adequately told on the screen without today’s post-Inception techniques: the scenes in weightlessness, especially. The effects gave it visual scope. This is a Big Screen movie, and I--normally a person to wait for things to come out on TV--heartily recommend you see it in theaters, if you can.
The emotional scope of the movie was as good as the novel's: better, in that the dragging pace of the end of the novel was not even hinted at. I saw reviewers who thought the bullying and young people fighting were disturbing, to which I reply that it's supposed to be disturbing. Card was making a negative comment on the human condition almost as profound as the culmination of the plot. That was the theme: the evil we can do in the name of good and self-preservation.
While I was fully aware of the devastating secret at the end of the film, my husband had forgotten it. I was able to appreciate the story knowing what shock it led up to while he was blissfully unaware of what was coming. He called the secret at the end a "gut punch." I was very pleased that he experienced the film on that level. This is how a person who had not read the novel will react. Please – this is like "The Sixth Sense" in that spoilers make it a whole different experience for the film-goer. I hope none of my “in-the-know” friends let on in advance what devastation and hope await Ender.