If you don't want to see a movie with an open ending, this is not for you. Script running similar to "the happening" and "the mist" (even some zombie attack movies)

So, the story have gaps, it will make you ask many times how? Or why? And probably you will not find and answer... Some parts are quite smart, other are illogical or quite not possible. But it's a movie... that doesn't explain itself. Is still enjoyable. Much better than "the happening" but still under "the mist"