While I don’t think it was a movie that could never be made based on the book, it’s obvious that at least in the promotional side of it, a fair bit of the twist from the book is being revealed. Which may be the main way to actually film it in a way, though based on what’s said here, it’s also likely the the characters involved don’t know the twist, which helps. Ender’s Game, based on the novel series of the same name from Orson Scott Cart is due out on November 1st, 2013 directed by Gavin Hood with a rather engaging cast that has Asa Butterfield, Harrison Ford, Sir Ben Kingsley, Hailee Steinfeld, Viola Davis and Abigail Breslin working together.
Ender’s Game won the 1985 Nebula Award for best novel and the 1986 Hugo Award for best novel.
In the near future, a hostile alien race (called the Formics) have attacked Earth. If not for the legendary heroics of International Fleet Commander, Mazer Rackham (Ben Kingsley), all would have been lost. In preparation for the next attack, the highly esteemed Colonel Graff (Harrison Ford) and the International Military are training only the best young children to find the future Mazer. Ender Wiggin (Asa Butterfield), a shy, but strategically brilliant boy is pulled out of his school to join the elite.
Arriving at Battle School, Ender quickly and easily masters increasingly difficult war games, distinguishing himself and winning respect amongst his peers. Ender is soon ordained by Graff as the military’s next great hope, resulting in his promotion to Command School. Once there, he’s trained by Mazer Rackham, himself, to lead his fellow soldiers into an epic battle that will determine the future of Earth and save the human race.