When Maggie finds the trapped fox, she returns to the house to get a gun. The closeup of the gun on the mantle reveals it to be a double barrel shotgun, but when Maggie takes it from the mantle it is in fact a .22 bolt action rifle.
Early on Maggie cuts off a finger on her left hand as the infection spreads. Later when she goes to visit Trent, she braces her left hand against the wall walking up stairs and we see her hand is healthy and intact, with no finger missing.
Maggie's eyes go from zombie cloudy to clear and back numerous times.
The film is set in the 2010s but the police cars are from the mid-1980s.
The sheriff's deputies identify themselves as "police"; the police and sheriff's office are two different entities.