This is hardly a masterpiece but it's not terrible either. If you go in expecting this to be filled with riveting drama or action or to simply be like many other films with similar subject matter, you're probably going to be disappointed. This isn't that. There's very little action and even the drama is relatively tame.
The story focuses on this broken family isolated in a mansion. They aren't in the center of what's going on. They aren't even paying attention to the news updates so the audience doesn't get much information. In fact, this almost apocalyptic event seems to mostly exist as a plot device to get this family back together and stress them out. The entire thing is just learning about this family and their history as they fight to survive what seems to be an apocalyptic event.
The science of the movie is well... is there any? We don't actually know much about what's going on, but it's probably not scientifically possible. That being said, it seems the idea of the movie might have been drawn from Lord Byrons poem, Darkness. So perhaps it wasn't meant to be scientifically accurate and instead just show a take on this dream that happened in the poem.
I think if you take the movie for what it's actually meant to be and do, it's not that bad. It's still no masterpiece and it's hard to watch sometimes, mostly because the behavior of the father really bothered me. This family is messed up. But if you like calmer movies with a little bit of an apocalyptic setting that focus more on individuals and families, you might actually enjoy this. But if you need riveting drama and action to keep you interested in something.. you should probably look for something else.