As far as a guiding philosophy goes for a pop-action thriller like World War Z, 'movement is life,' isn't bad. And for the first half of the movie or so, it follows its own advice. Similar to other recent zombie movies (Dawn of the Dead, Shaun of the Dead) the warning signs of what the rest of the movie will bring are subtle and buried until all hell is ready to break through. The television mentions 'martial law,' Philadelphia traffic snarls, and an increasing number of police ride past in motorcycles and helicopters. The first wave of the zombies washes over the crowd, viewed from above in a dramatic grand-scale fashion. I don't like the idea of speed zombies generally, and the transition from human to spasm-wracked undead happens with silly rapidity, but it's hard to argue with the jolt of watching thousands of people run directly at you.
I've tried to explain what I've liked about the zombie genre and basically I think it boils down to this: while two or three ghouls are easily dispatched and rather ridiculous, there is no quick solution to a zombie plague. You can shoot them in the head or burn them, but ultimately each member of the horde must be dealt with individually. There is no quick fix, no easy solution. Some find this rather depressing, past a certain point any rational person would take a look at the ruin of a world overrun with zombies and opt out. What makes zombie movies compelling is that it strips people down to the basic will to survive. Zombie movies are about resolving the question about which is stronger, life or death.
This is exactly the reason the book World War Z was so compelling. It asked again and again what individuals and governments might be willing to do in order to survive. By grounding the near-destruction of civilization in the themes of environmental destruction, global migration, globalization, and militarism, the book found something compelling to say about the present world.
World War Z has the same title as the book, just like I, Robot has the same title as a famous Isaac Asimov short story. If you can't forgive the movie for its original sin of having basically nothing to do with the book, than you probably don't need me to tell you stay away. If on the other hand, you're willing to judge the movie on its own separate merits, I would suggest renting this one. The big epic scenes aren't going to suffer too much in a home theater and the smaller claustrophobic ones might work better.
Perhaps inspired by the book, the movie trots out a few possible solutions to the zombie plague, searching for a cure, walling a city off from the invasion, or evacuating out into the ocean. But ultimately we see that the plague creates hordes of zombies too fast, determined, and numerous to be dealt with by old strategies. Your interest in the first half of the movie will depend on how much you can tolerate big scenes of rubbery CGI zombie tsunamis washing through alleys and streets of major world cities. The momentous sweep of these parts of the film mostly subdue natural disbelief, and quibbles about standard stupid action tropes (inopportune cell phone rings, squeaky doors, major speeches right in front of scenes of impending disaster).
Then things change.
The last third of movie and I'm going to try to avoid spoilers here, represents a severe departure from the tone and energy level of the preceding reels. After a mid-air zombie encounter, Gerry Lane finds himself stranded in a bio-medical research facility, the answer to the zombie plague close at hand but surrounded by zombies. Having followed the development of this movie, I know that it's about this point in the film that the original shoot went off the rails. The first version of the script had Pitt's character trapped behind lines in Russia, joining an anti-zeke militia, and eventually fighting a climatic battle in the snows of Moscow. For various reasons, this version of the movie was considered unsatisfactory and a completely new ending was filmed. The results aren't bad precisely but are incredibly derivative and disappointing considering what lead into them. It's as if Avengers had ended with Thor and the Incredible Hulk stuck in New Jersey, looking for a missing anti-cosmic cube lost in a government installation while catching glimpses of the Chitauri invasion on the overhead monitors.
Movement = life, and this movie decides in closing moments to play it safe, barricade its doors, and hope it will all work out.