Happened to run across the Ender’s Game movie, decided to watch it, even though I vaguely remembered hearing it wasn’t good. And it was actually…fine? I think, though, that it might only work for someone who already knew the book really well. The movie essentially was like a highlights reel of the book, hitting the big dramatic points, skimming over everything else.
(Possibly it would only really work for someone who loved the book, which I do, despite the homophobia problems with Card as a person.)
I’m not sure you could do that book as a 2 hour movie; it’s just too dense to get all the depth of characterization and relationships across. Interesting.