Man, kids sure can be stupid. Not 15 minutes into 28 Weeks Later—the sequel to Danny Boyle's lo-fi, super-creepy 28 Days Later, which reenergized the zombie genre way back in 2002—a couple of dumbass kids ruin everything for everybody. According to 28 Weeks Later's plot—which is an iffy thing to rely on, rickety and tired—London's recovered from the zombie outbreak of Boyle's film. Six months later, the zombies are dead from starvation, and US-led forces—doing our usual ill-researched meddling—have decided that the city's okay to live in again. (If that sounds like a fantastically dumb idea to you, kudos—you're officially more intelligent than any of 28 Weeks Later's borderline retarded characters.)

But, oh, right, those kids: All you need to know is that they're annoying, they're the ones responsible for bringing zombies back to London (thanks kids!), and they're also the main characters of 28 Weeks Later. Yep: While 28 Days Later followed shell-shocked survivors Cillian Murphy and Naomie Harris, none of that film's cast could be bribed to participate in this sequel—so now we're stuck with the teenage Tammy (Imogen Poots) and her whiny, 12-year-old brother Andy (Mackintosh Muggleton, whose name seems plucked from bad Harry Potter fanfic), who spend most of their time running away from their zombified dad (Robert Carlyle).

Likewise gone are the creepy psycho-sexual themes, discomfiting immediacy, and sharp writing of the first film: Instead, 28 Weeks Later simply boasts a higher budget, some carefully constructed shots of CG eye candy, a particularly misguided scene shot entirely in night vision, and way more fake gore. It's merely dreary and repetitive at first, with director Juan Carlos Fresnadillo content with zombies raging to an ambient soundtrack—but after a few goofily bloody kills, 28 Weeks Later gleefully jumps the shark when a low-flying helicopter's blades chop through a horde of the undead. It's a ludicrous gag, and one that worked far better a few weeks ago in Grindhouse, when Robert Rodriguez used the preposterous sight as a tongue-in-cheek joke. Fresnadillo, however, delivers the blood-splattered scene with a depressingly straight face. So this is how zombie invasions continue: not with screams, but with yawns and unintentional laughter. And stupid kids.