I like run-of-the-mill thriller/post-apocalyptic scifi as much as the next person, but I also enjoy a film that is art, doesn't tell all, and gives me more a cheap thrill. If you are looking for a film that hands you all the answers, some straight-forward post-apocalyptic tale of protagonists struggling to survive under the constant threat of zombies, aliens, pandemics, etc. and couldn't care less about artful cinematography, brilliantly imagined and acted characters, and can't explore and imagine and wonder along with the writer/director as you watch a film, this is probably not for you. Or if you're not in the mood for that today, move along and save it to your watchlist.
The setting is an After of some sort, a world with toxic clouds that roll in and threaten to choke the life out of the living. The protagonists, a man and a woman, are traveling to a place that can be called home. You get the impression that they have completed much of the journey. Along the way they find two towering buildings of a hotel with everything they could need for a while. The man is immediately at home in the hotels, but the woman, who seems more wild (great acting and screenwriting), who seems to remember less from the time before, regards the hotel and its comfort with skepticism and a little disgust. If it isn't home, it isn't where she wants to stay. But hungry, tired, and in need of shelter, of course they stay. And as they stay longer, the hotel and its modern comforts and old secrets change them. And while you'll get to know some of those secrets that are strangely terrifying and sad, you may not understand them all. I was held captive by the tension between the man and woman protagonists as they changed, as they kept secrets from each other, and the secrets themselves. Clearly a lot of 1-star reviewers watched it until the end too. There's a reason for that: this is great film-making, great screenwriting.
There's a lot of metaphor in this movie, and I suspect that some of the closure we crave so much didn't happen for the writer/director, either. The journey is circular--the characters don't get to an end but rather back to the journey itself, the substance in between having changed what they remember, maybe how they remember, and perhaps what they seek.