The zombie movie has been done to death, at least as far as I'm concerned. There have been so many over the years, and George Romero has accomplished every interesting twist or metaphorical take on it that anyone could hope to have. Then, 28 Days Later made them fast, and Shaun of the Dead spoofed the whole genre, so when we're confronted with another traditional zombie apocalypse film, I'm looking for even the slightest permutation here, anything to give it a new spin, communicate a reason why it was worth making.
What this movie gives us is Brad Pitt as the hero in a zombie apocalypse world, and that's about it. There's no new threat of any kind or any real difference to a traditional undead movie here, and the angle that it wants to take is to be a semi-realistic "how would the government react" in the case of zombies taking over, but what actually happens here is so incredibly unrealistic and depends on a series of extremely lucky coincidences for our hero that that premise is pretty much laughable. If you want to see a real-world approach to a global threat disaster movie, the film to see is Steven Soderbergh's Contagion, which this is kind of like a very mild, dumbed down version of.
As the movie starts we're plunged right in the middle of the catastrophe, as Brad Pitt's character Gerry is sitting in traffic with his wife (The Killing's Mireille Enos) and two kids when the city is suddenly swarmed with attacking zombies from every corner. When Gerry fights his way to safety, he's promised shelter for his family by his former employers at what's left of the UN, if he agrees to be sent to South Korea with a military team in search of a cure. This incredibly unlikely scenario takes place with Gerry of course becoming the sole survivor of the team and miraculously making his way across all corners of the globe in search of a cure as zombies attack every single area he lands in- but he always manages to make it out just in time, even though there are basically no other survivors to tag along with him. He's the world's luckiest man. What grounds the silliness somewhat is actually Brad Pitt's performance, as he chooses to play the role in a very somber, almost sad turn, looking like he's going to cry in every scene and managing to gain our sympathy for the ludicrous situations he finds himself in. He's just a very likable, sympathetic presence at all times and I do think someone else in the part would not be able to hold such a connection with the audience in a movie that takes itself this seriously.
Even though this film was plagued by rumors of reshoots, re-writes, and delays that forced the production to go wildly overbudget, there's no evidence of that here. It's actually not badly made, save for the CG zombies in shots that for me were kind of distracting by how phony they looked at times (something that has not been a problem in zombie movies of the past- all it ever took before was makeup on actual people). Essentially, this is a passable movie, it just leaves me wondering about the necessity of it. If you want to see zombies, there are plenty of better films out there (I'd recommend 28 Days Later), not to mention AMC's The Walking Dead, where you can get your fill on a weekly basis. But if you want to see Brad Pitt as an action hero, then this is your chance, and overall it's harmless enough to not label as one of the worst disaster movies you could find. It's simply one of the lesser.