Seeing the trailer, it immediately brought references to the popular multiplayer cooperative game Left4Dead and Left4Dead 2. The weaponry, the gore, and the manner of zombie deaths was quite similar, as well as the idea of "safe houses", if you pay attention to the movie.
Many popular films nowadays rely heavily on the CGI magic to work its way to a crowd's heart, but I liked Zombieland for paying real attentive detail to ironic humor and unexpected gags (as well as LOTS of make-up) in providing the comedy. The narrative style of the main character, Columbus Ohio, was also really funny in that he speaks in the matter-of-fact way of many born losers. He was perfect for the role. The constant reminder to the audience of his "rules" also brought some laughs, as they were flashed on the screen accompanied by a complementary scene, most often involving a gruesome zombie death.
I thought that the fact that there was less than ten names in the main characters list was cool; a few actors actually brought the movie to life, albeit with a little help from dozens of made-up stuntmen for the zombies. Less on the flash, more on the acting (though the acting was a tad dead sometimes).
Acceptable for a bored night out with friends, nothing brilliant, but should provide enough laughs to talk about later over some coffee. :)