Goofs

After Carter, Crystal and Maggie escaped the Mega Dome in a Dodge Caravan van, they hit a zombie road worker and the car's windshield glass broke instantly into the cabin. Modern car's windshields are made of tempered glass coated with a plastic transparent membrane in order to withstand breaks and ruptures without falling pieces on the passengers.

During general Lyons' first press conference under the rain, he says he has "authorization from the White House to destroy the threat through military action", Later on, he talks about a "great American city". Several aerial views show a great city indeed, but it is Vancouver, in Canada... The White House has no authority over Canadian territory.