When the giant hourglass is first shown, the top half is almost completely full. Yet in later scenes, when some sand has emptied into the bottom half, there is an noticeably insufficient volume of sand in the top half.
In the recap of the previous episode it was mentioned that the clock king deliberately left his watch to lure Batman and Robin into a trap. But there was nothing like that in the previous episode.
When Bruce and Dick rush to save Aunt Harriet, Burt Ward is clearly still wearing the eyeliner used to emphasize his eyes behind his Robin mask.
In the clock tower scene, the automaton strikers are obviously live actors painted bronze, and can be seen to move subtly while they are supposed to be stationary.
When the large hourglass is rolling horizontally on the ground, the film is obviously sped up.
To escape the Clock King's death trap, Batman tells Robin to slam himself against his side of the glass, while Batman does the same against his side. However, both of them slam themselves against both sides of the glass.
When Dick Grayson finds Clock King and his gang robbing Wayne Manor, he whispers to Bruce with his hand raised to cover his mouth. However he uses the wrong hand, so that his lips would still be visible to the criminals.