If you are thinking about watching a movie while playing a video game and take a glance every few minutes to see some disgusting monster, tearing a human a part. Look no further. You must see this state of the art movie with great visual effect. But if you are thinking about getting into the story you are in the wrong place. The story does not make sense, They have obviously done all they could to create these intense scenes with no background or explanations
PS: btw, their guns are probably not effective against these creatures, it's like trying to take a tank with a machine gun. Maybe humanity dissevers to be destroyed if they are that dumb!