Maybe this is a hot take, idk, but I don't think we should think of Annihilation the film as an adaptation of Annihilation the book.
"Film adaptation of a book" means translating the book, as best one can, onto the screen. I don't think Annihilation the film really does that. Because how can it? The Southern Reach is such an odd series, built around trusting the reader's imagination rather than "then the character does this". There's basically no clear plot aside from "Survive Area X (and maybe figure out where it came from)." I think Annihilation the film should be more considered inspired by the books. Because it's so different, because they had to change and interpret so many things, it's hardly even the same story. I think both the book and film are amazing in their own rights, and it's unfair to hold them to similar standards. They're different stories in different mediums. Can they really be compared fairly?
When I saw the trailer for The Marsh King's Daughter, I wanted badly to see it. So I read the book first. Then watched the movie. And the movie, I think, was better than the book. But this story could be compared more fairly, because it's clearly the same story, even though liberties had been taken; had to be taken, due to different mediums. You can't say as much in a movie as you can in a book.
Even films that are very similar to their book counterparts like Odd Thomas and The Girl With All The Gifts are like this. Because it's a different medium. But they're still clearly the same story between page and screen. Annihilation book vs film brings it to an extreme, so much so that they're not really the same story at all, aside from that core of "Survive Area X." There's no tower, no Crawler, in the book they don't use the term Shimmer at all, and both the biologist and her husband make it out at the end, more or less. A book to film adaptation needs more core plot points than just a core idea. Going back to The Marsh King's Daughter: despite the glaring differences between book and film, much of the core plot was the same, leading to it feeling like the same story despite the changes. I actually much preferred many of the changes.
I don't think Southern Reach was ever meant to be adapted into a film. It just doesn't take it well. So maybe we should stop thinking of Annihilation as a film adaptation and more as something that was greatly inspired by Vandermeer's trilogy. We don't have to pitch them against each other. They can both be good in their own right.
