Continuity mistake: When Peter has just killed the child zombies and another with a messed face is in the doorway, we see Steven outside aiming a rifle and it is cloudy, dreary weather. Peter dives out the way and lands by a window and we see that it is now pitch black, then Roger steps in and shoots the zombie from outside and it's only just overcast.
Continuity mistake: Just after the raiders manage to get into the mall, one raider uses his sledgehammer to knock a zombie wearing a black t-shirt off his feet. 5 seconds later, the same zombie can be seen walking past the same raider.
Continuity mistake: When the bikers are stealing the zombie's wallet notice Blades in the background cheering his buddy on while just standing next to a zombie. (01:48:30)