This film introduces a series of blunders. Just one example is that even though Hannah Banks is not "telepathic" like her mother, she plays a very important role in the movie in the sense that everything she ever did was a portent of what was to come; from questions she had, to the name of her class project.
Another example of this particular blunder is General Shang, who also possesses no future-knowing powers, yet insists that the protagonist Louise Banks needed to hear his wife's dying words for some unknown reason...Yet another example is that the aliens landed on earth, and even though the movie is dedicated primarily to understanding them, at the end we still don't know why they arrived.
When Louise's partner Ian understands the aliens' message, it is revealed that they are asking for help. We never see what they need help with. Perhaps because they mention needing help in the next 3,000 years. If they mean the year 5317, the people the aliens asked for help are all going to be long, long since dead. And you all just came to the only logical conclusion: Time capsule, right? Fine, that's logical...except there would be no way to determine that the people who find the time capsule would take the message seriously, or have kind enough hearts to help the aliens if they did.
Yet another example is that while the ship looks rather small from the outside, it goes on as far as the eye can see when the characters enter the vessel. Maybe that's a reference to the Tardis, but based on the septopods' anatomy, they wouldn't even be physically able to command a vessel; not like a shot of the dashboard was ever included in the film.
For my final example, while Ian and Louise flirt on and off, they never actually touch. Yet at the end of the movie, when they embrace, Louise says she had forgotten how good it felt to be touched by him. Throughout the movie, I was under the assumption that when they met, it was awkward because he was her ex; and had he not been so surprised to learn she was married once, the ending scene would have made complete sense.
For these and even more mistakes, I found this film to be a confusing disappointment, where even the crew was uncertain what was going on.