As with most zombie movies the plot is rather contrived and unbelievable (even if you accept the existence of zombies) but if you want to watch zombie movies in the first place that is something that you are supposed to be immune to.
This is another variant of zombies being created by some virus and rapidly taking over most of the planet. As I said, the entire story is somewhat unbelievable. When I first read about zombies as a kid there was always some supernatural/magic stuff involved. I think I liked that “explanation” much better than the virus nonsense which just have too many holes in it. For example there is no way a virus could make human bodies roam around aimlessly inside a sterile laboratory for days without nutrition. Well, as I said, it is a zombie movie so one just have to get over these little issues.
As an action movie with zombies as the main adversary it is a fairly good movie. The action is solid, the special effects okay and the entire movie continues at a reasonably brisk pace. Pitt is also doing a decent job of his role. There are few of the other actors that are very memorable though. The scenes where the zombies pile onto each other to scale walls and even reach choppers are rather cool. The movie is not very gory for being a zombie movie. Whether that is a good thing or not depends on the viewer I guess. Personally I do not mind some gory stuff in zombie movies.
There are a few annoying parts which Hollywood always seem to have to throw in. For example, the world is on the brink of the apocalypse and Lane and his wife just doesn’t want to get involved. What the f…? Also why do people always let their kids wander away in situations where they really should keep track of them? Not to mention how clumsy people always get when they have to sneak around and be silent. These things are just annoying.
Anyway, this movie fulfils its purpose as two hours of action-filled but not too intelligent entertainment quite well.