Cargo presents a very familiar premise: A dystopian future with a desolate Earth is the backdrop for a thriller set in the confines of a cargo ship.
And while it starts off as what seems to be the usual Alien clone, it quickly evolves into a very complex mystery, with a far-reaching story arc. If I were to rate the first hour of the film it would be a solid 8/10 suspenseful hard sci-fi mystery/thriller.
However, after the first hour problems begin to arise. The plot starts having cracks. Characters start doing irrational things with hardly any explanation, simply so that their actions can act as a vehicle for the next scene. The mystery reveals itself but the implications it presents are mishandled. The movie starts dropping speed and stretches itself without any real need to do so. (And I have to say this but I hate it when characters are told they have X minutes left to do something important, but they take their time to walk slowly from point A to point B as if they have no cares in the world).
I think the creators could have done a far better job and it's a shame that they didn't because the film excels in most other sectors. Aside from the flaws I mentioned above, the characters are not explored much, but what we do see of them is consistent and believable. The art direction really nailed it, and with a better CGI budget they could have blown minds. And although the direction aboard the ship was discreet, it nevertheless impresses.
I'll give more chances to the people who made this, they certainly deserve it. If you enjoy space sci-fi thrillers, with an emphasis on hard sci-fi, you will probably enjoy this.