I went to see this having read the story it's based on, whereas attimes_bracing knew only the barest outline of the film's plot. We both came out very much liking it.
As an adaptation it is not at all bad, and Ted Chiang is on record as approving of it. I was a little concerned by the first trailer but that seems to have oversold the 'threatened military confrontation with aliens' thread that was added for the film. Certainly, what we got was about as far from the stereotype of the monsters-versus-the-military sf blockbuster as you could imagine, and was beautifully filmed (although the Montana Tourist Board might fret at the implication that the state is permanently dull and rainy). The depiction of the Heptapods and their language was if anything even better than in the original story, although I do wonder if anyone on the production team had seen Torchwood: Children of Earth, which also featured starfish aliens barely glimpsed through fog behind a glass barrier.
Arrival fails the Bechdel Test, but probably – depending on your interpretation – passes the Mako Mori Test.
For purely parochial reasons, it would have been entertaining to see more about the British attempts to engage with the ship said to have appeared over Devon. as depicted on this version of the film poster, although for good reasons the film concentrated on the US team's interactions with its non-Anglosphere counterparts. From the little we did see, one rather suspects it involved posh Oxbridge types trying to enunciate English loudly and very slowly to the Heptapods...