Continuity mistake: At the beginning of the short, we see Dr Jekyll entering his laboratory and you can see the door is plain. But when Sylvester enters the lab with Tweety in his hand, the door now has a window.
Continuity mistake: When Sylvester lands on the ground after using Tweety's feathers to help him, he drops the feathers on the ground. But when Tweety lands on him in the next shot, the feathers are nowhere to be seen.
Continuity mistake: When Sylvester runs to the window when pursued by Tweety, there is a door next to him that has a number "19" on it. But when we see Sylvester looking out of the window, the "19" on the door has gone.
Continuity mistake: When Tweety (as a monster) says "You bad old puddy cat!" to Sylvester, you can see that Sylvester has a drawer open in front of him. But when Sylvester falls to pieces in the next shot, the drawer he had opened is now shut and he is now standing in front of an open drawer in the bottom left hand side of the cabinet, and when Sylvester runs off in the next shot, the drawer is closed.
Continuity mistake: When Tweety jumps through the window into Dr Jekyll's laboratory, you can see there is nothing on the table, but when we see Tweety in the next shot a bottle of the Hyde Formula and some chemistry equipment have appeared.
Continuity mistake: When Dr Jekyll enters his laboratory at the start of the cartoon, he locks the door with his key. After drinking the Hyde Formula, he turns into Mr Hyde for a short time before going back to Dr Jekyll. When Jekyll leaves the laboratory, he opens the door without unlocking it.
