8.6/10 stinky bananas
Very good movie.
Pros:
Unique and well executed story
Cool visual effects
The plot has some difficult concepts (the intertwining of time and language), but everything is well explained and relatively easy to follow.
Con:
There is not nearly enough emphasis on the invasion at the beginning of the movie. Everybody seems remarkably calm about the entire situation. I would be pooping my pants.
You've probably already seen Arrival. End of review.