Great acting and interesting concept, BUT... a lot of plot holes:
How come scientistes couldn't figure out that increasing sound waves will incapacitate the beasts/aliens.
If you can, simply, kill the aliens/beasts with guns, wouldn't the army have been dispatched to seek and destroy them?!
Why did the parents leave the kid to walk behind them (at the beginning of the movie). The logical order would be adult up front, children in the middle and adult at the back.
I give it a 2.5/5