George A. Romero’s Night of the Living Dead (1968) ended with a crushingly ironic scene in which the lone survivor of a zombie onslaught is mistakenly shot down by the authorities. When Romero made The Crazies (1973), he managed to spin that idea into an entire story: after the U.S. military accidentally unleashes a bioweapon on a small town, the uninfected have to protect themselves not only from their mad-dog neighbors but from the trigger-happy soldiers trying to contain the epidemic. Poor distribution doomed the original movie, though Romero has stuck around long enough to serve as executive producer of this respectable update by Breck Eisner (Sahara), which is getting a nationwide release. There may not be any second acts in American lives, but at least there are plenty of remakes. With Timothy Olyphant and Radha Mitchell. R, 101 min.