The first twenty minutes were the usual last man walking around on earth movie. It didn't do anything for me and I thought I was in for a pretentious slow bore. I was happy that some energy and even humour came from scenes of a breakdown. I expected the movie to be about this. But then another character enters the movie and it changes direction again and the time flew by. I was glued.

What this movie excels at is when its finished you question what you've seen. Did an American government project destroy the earth with the energy network (kind of like a cloud network of energy?) But in the end the network is still up. Unless not all the earth was effected. It could have been a secret weapon.
Maybe Zac is dead but he is somehow trapped in an alternate universe? The other characters remember dying ao perhaps they died at a specific time when the energy project was doing something and they ended up together.
That ending image? It'seems a mystery. Can Zac not die? Does he travel universes or realities upon death? Did he kill himself at the right time again to still be alive? The planet near on the horizon looks like Saturn. Is he on an Earth like planet or Earth? Why does he have his tape recorder? Is he really still on Earth and all this time has been used in a project without his knowing and is provided with a tape recorder for feedback? I don't know.........
The science is pretty vague in the movie but the experience will make you think and look forward to a second viewing.