http://en.wikipedia.org/wiki/The_Divide_(film)

I think Bethesda/Obisidan were inspired by that film to create The Divide.

Too bad no one likes this movie to put some actual info on it.

This is the best description I could find someone's review

I attended the almost sold out screening of "The Divide" at Montreal FantAsia Film Festival with special guest Xavier Gens (director), Michael Biehn (actor) and Michael Eklund (actor).

The crowd, as always in FantAsia, was very engaged and energetic. However, as the horror story unfolded (not exactly horror genre film, save for a few scenes, but horrific in the psychological debacle of its characters), the crowd got quiet and silently absorbed the very well-crafted human drama. The performances felt real. The mood was perfectly dark and doomish. This post-apocalyptic take on humanity is not the most positive, but it is positively one of the bests! The cinematography and few special effects are good, especially for the budget. We learned in the Q&A that the film was going to be canned, but that an intern in Winnipeg (Canada), said that his parents could finance the film and fork the few millions needed to finish the project. Gret thing they did! This detachment from market-driving founding also allowed for greater artistic freedom and the three guests really explained how Xavier Gens challenged his actors (and some times cameramen) to improvise, be creative, immerse themselves in their characters, and serve the story and the film. The two Michaels were thrilled to worked this way and brought many contributions, while they also mentioned how Lauren German was a more by-the-book actress and they all had to event ploys to get her to be surprised and spontaneous. They all mentioned it was the best filmed to work on in their lives, although staying in character after shooting made for some tense sets and after-set (hotel) interactions. Gens choose to film the movie in chronological order, encouraged his actors to starve themselves (which Eklund did to the maximum) and let their mind go as the film reel rolled. Having written a novel in chronological order, I understand exactly what latitude that gives in character development. The story takes unexpected turns, but feels right, cognitive and consistent.

The story with its sci-fi elements briefly introduces a world of wonder, before shutting the door closed on hope and humanity. It is saved by sparkles of effective comedy, but transgresses into a struggle to survive at any price. What is there left? Humanity? Dignity? Love? Compassion? Not really.

As dark is it it, this vision hopefully encourages us to do better in our own lives. No need to wait for a nuclear explosion to figure out what is our desired behaviour for betterment.

So sci-fi elements, post-apocalypse, and horror. I think it could possibly be an idea, or maybe a coincidence.

Well the film was released a few months ago, so I wouldn't say it was a coincidence.