Continuity mistake: When the bikers ride through the zombie infested town for the first time watch when Big Daddy is shot at. The windows behind him are shattered by the bullets but a few seconds later are fully intact. This may be hard to see as it is dark but they are back, easiest way to tell is by the reflection from across the street.
Visible crew/equipment: When Dead Reckoning (the massive truck) is starting to be surrounded by zombies there is an extra spotlight mounted on top of it. It wasn't there in any of the earlier scenes. The shot where it's visible has Dead Reckoning on the right, eight or nine zombies on the left all walking by, and a few powerlines visible in the background. It looks like they just put it on top to give some extra light on the zombies.