Sounds like Gillan Flynn wants to have things both ways. First, she said that the ending of the film version of Gone Girl will be different from the book. David Fincher made it sound very different, telling Entertainment Weekly that star Ben Affleck was so “shocked” by the changes that he said, ‘This is a whole new third act! She literally threw that third act out and started from scratch.’
But in an answer to a question during a Reddit discussion yesterday, she stepped back from that quite a bit. Below is her response:
Tell your girlfriend not to worry—those reports have been greatly exaggerated! Of course, the script has to be different from the book in some ways—you have to find a way to externalize all those internal thoughts and you have to do more with less room and you just don’t have room for everything. But the mood, tone and spirit of the book are very much intact. I’ve been very involved in the film and loved it. Working with David Fincher is pretty much the best place to start for a screenwriter. Screenwriting definitely works different parts of your brain than writing a novel. I do love that with novels, you can really sprawl out–it feels quite decadent. With screenwriting, you have to justify every choice. It’s a nice discipline, but definitely not decadent.
So, take your pick. If you want a different ending, quote the Flynn of EW. If you don’t, quote the Flynn of Reddit.