Continuity mistake: When the gang of survivors goes to Andy's gun shop, one of them shoots a zombie and he proceeds to fall on his knees. The scene cuts to the gang and then to the charging zombies and the shot zombie falls again.
Factual error: When the survivors are first in the mall, you can see a store called Roots with a Canadian beaver logo. While the movie was filmed in Canada, it is supposed to take place in the USA where Roots has a different logo.
Revealing mistake: As Ana is driving away from her home, when we see her car driving from a shot high above, we see a car crashing in to a gas station making a huge explosion. However the trees a few feet away from the explosion don't move. The shockwave would have made them react at least a bit.
Continuity mistake: At the beginning of the movie, when Ana is escaping from her husband, she crashes into the bath and in the process pulls down the shower curtain and rail. The shot from above shows the curtain rail landing on top of her, but when the shot immediately switches to show to show a close up of her sitting in the bath, the rail appears to be propped up just behind her right shoulder.
Continuity mistake: At the birth of the zombie baby and the shoot-out, the pregnant girl gets shot through the left eye blowing her eye socket apart. Afterwards, the main blonde girl surveys the area and now the pregnant lady's left eye is undamaged.
Continuity mistake: When the group goes to rescue Nicole from Andy's shop it it is evening, when they return and must evacuate the mall it's night, but soon as they clear the horde in the parking lot it becomes early morning.