It's an interesting movie, albeit somewhat bogged down by clichés (squid-like aliens
again?), a simplistic world view (was the Chinese general's wife named "Martha"?), and an all-too anthropocentric narrative (hint: very few
terrestrial animals
understand imperative pointing).
As far as first-contact movies are concerned it's not bad, and the time-jumping language is cute. But still, in this regard Tarkovsky's Solaris still reigns supreme. For Lem (the author of Solaris) communication with an alien life-form is an absolutely hopeless endeavour (contact with humanity is more of a happenstance initiated by us with little regard of our existence). The (maybe) sentient ocean Solaris is truly inscrutable, both intellectually and emotionally (even the applicability of those words being in doubt). As such, the exchange which takes place may not be a form of communication at all, but some sort of unintentional radiological side-effect which materializes conscious and sub-conscious thoughts and memories (because ultimately the story has to be about something we can relate to).
But on its own terms Arrival is a decent sci-fi, with a refreshing dose of sobriety. 7/10.