Jesse Eisenberg stars as a college student trying to make his way home to Columbus through a zombie-filled apolcalypic future hellscape. He's a whiny little dweeb, but survives by following his rules of safety, such as do cardio (so you can outrun the zombies), fasten you seatbelt, don't be a hero, check the back seat, etc..
Along the way he meets Woody Harrelson, on his way to Tallahassee. He's a bad-ass, reckless zombie-killing maniac with a craving for twinkies. They meet up with Wichita and Little Rock (Emma Stone from SUPERBAD and Abigail Breslin from LITTLE MISS SUNSHINE), a pair of sister con-artists. And they have wacky adventures and kill a lot of zombies on their way to Pacific Playland, an amusement park in Southern California that's allegedly zombie-free.
In short, this movie delivers what it promises--cool, fast action and silly gags involving zombies. Just don't think about it too hard, or you'll realize how much doesn't makes sense (it's much easier to just accept they're going to an amusement park because the filmmakers thought it would be cool to kill zombies in an amusement park, rather than for any reason given in the film). And Columbus's voice-over narration is a little too much. Sometimes it's a good joke or gives useful information, but at least half the time it could be cut out. Prime example: it's well established that seat belts are one of his important rules. So when he relaxes on the road with Wichita driving and unbuckles his seat belt (to try not to look so uncool in front of her), we don't need his voice-over explaining that he broke a rule.
But that's a bit of a nitpick. The crowd I saw it with seemed to eat it up (several came in zombie makeup), and frankly I ate it up, too. It was lots of fun. Oh yeah, and no spoilers but I'll say that the BM scene was by far the best surprise in the movie (that probably doesn't mean what you think it means).