Even though there is non-stop action, you are not interested. You don't (at least I don't) care about any of the characters. I didn't even want to watch the ending. But for some strange reason I did. You don't just not care about the characters, but you also don't care about the movie, how it ends or if there will be a sequel (which there will be... sadly).
How they got all these big names to produce this I will never know (Ben Afflek, We Craven, Matt Damon). The script must have been half ways decent, though in my opinion it wasn't... but what do they know about the horror genre? Obviously NOTHING!
The only part that somewhat impressed me were the way the creatures that came from nowhere looked. That was pretty cool. But where they came from, why they are evil, why the want the people, we never find out. There are other unexplained things, that you will find out if you rent this. But trust me, it's not worth the money.
I really don't understand what people liked about this movie. I will say it started out like it might be good, but it wasn't.