When Dr Smith lays down on the table for a massage from the robot, the towel around his neck changes between camera shots, as does the height of the robots arms.
Obvious stunt double for Guy Williams in the beginning when Gromack raises Professor Robinson above his head.
The weights on the bar bell are obviously foam rubber, the porous texture can be seen at times.
The wrestling promoter (as Smith was about to start his fight) introduces him wrongly as Professor, rather than Doctor Smith.