Great film. If you think you're watching the all to familiar alien invasion movie with blockbuster action, this ain't it. It closely resembles a indie flick. Its complex and thought provoking. It has all the overtones of living in a fascist state where drones can track, see and hear your every move via implants. And then the insurgents that will not accept living under those conditions. The espionage tactics filmed is the real story. The aliens are somewhat of an afterthought and don't have much screen time.
It can be a little confusing and you really have to pay attention but its worthwhile watching it multiple times