Powerful and terrifying. I understand the negative reviews - people expected this to be a typical disaster movie that spoon-feeds the story to you. This is a movie to make you think and reflect.
The setting is apocalyptic, but the story is about how we have become helpless consumers who prioritize our entertainment and isolate ourselves from any sense of community. And how that will be our downfall.
The folks who are leaving one-star reviews are really proving the point of the movie. They weren't entertained and so it has no value.