Pete, maybe that second sentence should have been put in Spoiler mode. But yes, it's exactly the same in the movie. The action had to be greatly constricted to cram as much of the book as possible into a two-hour movie length. As a result, there's very little sense of the passage of time (probably accounting for that too-fast quality Lorna mentioned). The final battle was definitely rushed; I think they missed the boat on that, settling for sparkly F/X instead of a step-by-step strategic attack. I don't quite understand the several references to Peter, Ender's older brother whose role was cut from the movie. Why mention him at all? Perhaps planting hints for a sequel?
But in the end, the success or failure of the movie rests squarely on the shoulders of the young actor playing Ender. Asa Butterfield met the challenge, no question of that; in fact, he carried the movie. The 16-year-old brought such intensity to the role -- the kid is a real presence on the screen. I believed him as Ender; everything else is secondary.
Oh...and Petra and Valentine look too much alike. I sincerely hope that was not intentional.