Oliver Stone’s effective if hokey 9/11 docudrama focuses on the two Port Authority policemen (played by Nicolas Cage and Michael Peña) who were rescued from the rubble of the Twin Towers, their families as they wait for news, and a former marine (Michael Shannon) who winds up on one of the rescue teams. An exercise in flag-waving, it evokes nostalgia for World War II epics and the camaraderie of Stone’s Platoon, stroking Americans’ egos about their innate generosity but overlooking, except for a brief end title, all the citizens of 86 other countries who died in the attacks. Able newcomer Andrea Berloff wrote the script. With Maria Bello and Maggie Gyllenhaal. PG-13, 125 min.