In a scene in which a Dalek succumbs to the effects of the Thals' drugs, the Daleks in the background are flat photographic blow-ups. The wooden bases on which they are supported can be seen at the bottom of the shot. A change of camera angle makes the flatness of the blow-ups obvious.
The creature rising out of the swamp is supported on a rubber ring, which is inflated to give the impression of movement. The rubber ring becomes clearly visible as it is inflated.