Revealing mistake: Though the Village isn't supposed to have automobiles (only the little "golf cart" transports), there are several parked cars visible in the shot of Rover floating down to attack the fleeing Villager.
Revealing mistake: At one point, Rover rolls past the Village retirement home, but the film in this sequence was for some reason shown in reverse. Smoke from the building's fireplace is flowing back into the chimney instead of coming out.
Revealing mistake: When Number 6 first enters the bedroom, the light that hangs from the ceiling is moving as though someone has brushed against it. But there's no one else in the room.
Revealing mistake: Number 6 is supposedly flying the helicopter, trying to escape from the Village. There are shadows from the rotor blades crossing his face as he pilots the aircraft. But look closely at the top of the transparent cockpit bubble over his head: you can see the real copter blades - completely stationary and not moving at all.
Revealing mistake: No automobiles are permitted in the Village - ever. Yet in aerial shots, a black car is sitting behind Number 2's residence.
Revealing mistake: When Rover attacks Number 6 on the beach, in one of the shots of Number 6 falling to the ground, you can see a tether keeping Rover from roving too far. (00:31:47)
Revealing mistake: Obvious stunt double for Number 6 when he jumps out the way of the buggy car on the beach during his escape attempt. (00:31:01)
Revealing mistake: When the helicopter lands in the field with Number 2 and Number 6 inside, if you look as it sets down you can see a different man (an actual pilot) flying and not the dwarf butler. He isn't even wearing the butler's bowler hat. (00:16:57)
Chosen answer: We were never told. In the series finale [Spoiler alert] Number 6 demands an answer to that question, only to be shown his own reflection.
Jean G