Continuity mistake: When Peter and Brian are escaping from the locals in their car, they go over a ridge. They freeze in midair and a voice says "those Griffin boys..." and the screen goes black. Then, in the next shot, the whole landscape is different. Even though the angle of the shot is different, that doesn't account for the disappearance of Chris and Sam or the colour-change of the sky.
Continuity mistake: In the scene when Peter and Brian crash through the wall in the car during dinner, Lois is standing by the table with oven mitts on. In the next shot when Lois asks Peter what he's doing the oven mitts are gone. There was no time to take them off and nowhere to put them either.