I saw Arrival during Toronto Film Festival and went to watch it again over the weekend. "Story of Your Life" is one of my all-time favourite short stories -- really, that entire Ted Chiang collection, "Stories of Your Life and Others", is wall-to-wall brilliance and I cannot recommend the book highly enough -- and remain impressed at how effectively they tackled something I thought was nigh unfilmable. There were significant departures from the short story, but I thought they managed to stay true to the core conceit nonetheless, which is no mean feat.
I still wish they'd found a way to include the digression into Fermat's Principle from the book, which would have given Renner's character a bit more to do other than look pretty and act supportive (not that there is anything wrong with that!) Plus, it dovetails nicely with the linguistic elements in explaining some of the reasons why Heptapods perceive the world as they do. I also feel like they didn't spend near enough time shedding light on the analysis of Heptapod B (the written language) and how not only deciphering it but the ACT of writing it and immersing oneself in it, is essential in understanding their worldview. Tl;dr I wanted the movie to be nerdier but understand why they short-charged that element from the story, etc.
The external conflicts i.e. the international incidences and the whole thing with the Chinese General, are not present in the short story. I mean, it's realistic that it'd trigger an international incidence like that, but I dunno. It felt more like a distraction and borrowed from a way more conventional SF/action movie.
One thing that got me thinking a bit deeper -- in the story, there is quite a bit of discussion about free will vs. predestination, which really is the meat of the thing. The original story takes a more... fatalistic seems like the wrong word. More philosophical approach to it? You can perceive the future and the present at the same time, and you enact, or "perform" the action that will lead to the future you see with grace and clear eyes, but I never got the sense that there was a *choice* not to do it, to break free and change the course. In the movie, it feels like Louise has a choice, but chooses to embrace the joy and the pain her time with her daughter brings (hence Ian leaving her for "making the wrong choice"). It's just as moving, but the nuance is a little different. I'd love to hear what other folks who'd also read the story thought about that.
Anyway, mad props to Amy Adams, who has rarely been better. I also thought the score was dynamite. I've been playing Max Richter's On the Nature of Daylight (featured prominently in the film) in a loop since I watched it.