The must-see reputation of that romantic zombie comedy Shaun of the Dead (opening 9.24) is a bit overblown, I regret to say. The first third has delicious wit and invention, but the second two-thirds don’t sustain this. The Ain’t-It-Coolers have been far too obsequious in kissing this movie’s ass. Director/co-writer Edgar Wright and writing partner Simon Pegg’s script is about two London slacker-somethings in their late 20s dealing with an onslaught of flesh-eating ghouls. The problem is that the zombies aren’t theatening enough. They walk and react way too slowly, so no live humans are in any kind of serious jeopardy (well, some but not enough) and so the story tension suffers and it all goes down a notch or two. “We are on the cutting edge of zombology,” Pegg claims. And they are, I suppose…in a sense. Especially if you equate “cutting edge” with “check your brain at the door once the second act begins.”