If you're a fan of the novels, walk away and never look back.

Rating: 4/10 (1 November 2013)

As a movie, I give this 6/10 As an adaptation of my favorite novel of all time, I knock it down to 2/10.
I went in thinking I would hate the movie because the age of the actors they used to portray the children, Viola Davis playing Major Anderson, and a few other similar points, but honestly by the end of the movie I thought it worked out perfectly. Asa Butterfield as Ender and Harrison Ford as Graff both came off a little strong in their roles, but otherwise they did a great job. Ben Kingsley's portrayal of Mazer Rackham was probably the most accurate in the long run.
As far as being just a movie goes, I got the feeling that it was very rushed. Anybody watching it without having read the book will get this inevitable sense that there's something missing. The movie clocked in at 2 hours. It's my belief that any movie based on a novel, and one with as much detail and character development as this, should at least top out at 3 hours. Another hour and they really could've done a few things much better.
The visual effects were really well done and although they went with a lot more of a technological approach than what the original novel had envisioned, it adapted well to the concept. The costumes were awesome, the station, particularly the Battle Room, was breathtaking, and the soundtrack was appropriately epic. Basically aside from the script itself, the entire movie was really well done and had the makings of an awesome adventure.
As for those going in with the book under their belt, this is the most heartbreaking part. Everything they did was out of order or just plain wrong.
1. The battle with the Formics in the beginning is the second encounter, but it takes place on Earth whereas the second battle should've taken place in space out by Saturn. (anybody that's read Earth Afire knows crashing a Jet into a Formic ship wouldn't have done squat to it anyway.)
2. The school in the beginning was a military school instead of the traditional elementary school he attends in the books.
3. On the shuttle heading to Battle School, Bean is already present on the ship instead of being a later launch group where he first meets Ender (and is made an example of) after forming Dragon Army.
4. When in his first battle with Salamander, Ender is supposed to do nothing and in the second battle, he disobeys orders and fires at one man that forces a tie (the system for opening the enemy gate is completely removed from the movie)
5. Ender never gets traded to Rat Army even though it's mentioned that Bonzo wants him traded in the movie. Ender is instead promoted directly to Commander. (BTW, they spend the entire movie pronouncing Bonzo's name incorrectly. This was a point of focus in the novel that they should've had the decency to take 5 seconds to include.)
6. As Commander, they only show a 10-second clip of Ender's first training session and they skip all of the battles except one. Additionally, Petra and Bernard both fought for Dragon when in actuality Bernard hated Ender and Petra was a Commander on her own team.
7. After the fight with Bonzo, which was poorly choreographed and was less martial arts and more flailing and brawling, Ender knows he killed him.
8. Eros wasn't blacked out on the surface, the facility wasn't in tunnels underground, and in fact the surface of the planet had a breathable atmosphere.
9. In Command School, Bernard is again present as a member of Ender's Jeesh. Additionally, Ender actually had missions failed during his "Training" with Mazer Rackham, which should've never happened.
10. After recovering from ending the war, the invasion by Russian loyalists never occurred, none of his Jeesh besides Petra were there, and after wandering out onto the surface of the planet, he discovers the Queens egg on the surface of Eros (along with a living queen close to death)
11. In the end, instead of taking a colony ship with Valentine and becoming Governor of a new world, he sets out alone to find a home for the Queen.
In addition to getting a lot of details blatantly wrong, they've cut off the ending in a way that makes a sequel with even remote accuracy to the novels impossible. With the right script writer (I could've done a better job) they could pull off sequels, but honestly in the state this series is in now, I don't want to see another one.