This movie really makes you think, tho the ending could have been better, 3 or 4 more minutes could have made the difference. I was engaged the entire time, and as most people have pointed out, there are several loose ends, we never get to know "how it ends" but we are living vicariously through these characters, we get to feel and understand their confusion and fear. And in the end, they dont know what's going on, why should we. If this movie had better reviews we may have gotten a sequel where we got to see what happened to ricki, if adam Dupont ever made it home, if sam and will make it back to Chicago to Sam's mom to deliver the news her father is dead, to find out if the whole world is gone or if there will be some civilization left. But the writers used real geological events that could end the world we live in to tell the story, you just need to know enough about our earth to understand.