Sometime in the last 20 years zombie slapstick became a primary genre of the movies, right up there with action, teen musicals, and bad Jennifer Aniston romances. It carries expectations, it observes rules, and, as with Oscar-bait period dramas, the Brits have a tendency to do it better. At least they did with “Shaun of the Dead’’ in 2004.
With the smart, gross, extremely funny “Zombieland,’’ the Americans successfully fire back. Written by Rhett Reese and Paul Wernick and directed by first-timer Ruben Fleischer, the movie makes no claims to greatness and may even enrage zombie-movie purists, since the undead dispense with the classic Romero stagger here and sprint at top speed toward their victims. What “Zombieland’’ has instead - in spades - is deliciously weary end-of-the-world banter.