Visible crew/equipment: When Barbara is running around the house to find a way in, someone backs up (possibly with a camera in hand) behind a tree.
Revealing mistake: As soon as Ben fires the first shot from the rifle you can plainly see it's a fake. Not so much from the look of it, but by the fact that there's no kick back whatsoever. The bullets you see him loading it with look big enough to give a pretty good blast. Even a .22 caliber would have more kick than what he's using. His rifle shoots like a BB gun. (00:45:35 - 01:28:30)
Factual error: The truck's gas tank is said to be empty, but is able to explode spectacularly later on. An empty gas tank may spout a jet of flame, but will not have enough force to rupture and damage the truck, a full tank of liquid gas will not burn unless vaporized. Simply put the truck would not explode in that Michael Bay fashion.
Continuity mistake: When they are throwing the molotov cocktails out the window to let them get to the car, they throw one in front of both sides of the vehicle. However when the 3rd and 4th cocktails land, the first two which were just burning are now gone and there's no burn marks on the ground.