Audio problem: When the lion walks on stage, the audience becomes completely quiet and all that can be heard is the sound of the lion's voice. Behind him is only a curtain that hides the orchestra from view. Once he finishes speaking, he turns around and the curtain opens, and suddenly you can hear the orchestra doing sound checks on their instruments and it is loud, the lion tapping his podium to quieten them so they know the concert is about to start. This means merely a curtain was keeping their sound check from being heard at all until it was open? (00:02:25)
Continuity mistake: In the theatre, a baby goose and his father are watching the show and you can see the baby goose is sitting at the far end of the row. But when the other audience members turn around to try and silence the goose, he now has two empty seats beside him.
Continuity mistake: When Porky arrives home, you can see a window looking outside to the right of the front door, but when Porky shoots the man upstairs a second time, the front door now leads to a hallway with a staircase.
Continuity mistake: When Goofy searches through the dresser drawers one of the ghosts causes trouble, then Goofy breaks through the top of the dresser and winds up trapped inside, but when all four ghosts appear the dresser top is perfectly fine and that damage has vanished. Also, two of the drawers (one large and one small) fall out of the dresser, but as the four ghosts are pushing the dresser those two drawers have reappeared in their proper places.
Continuity mistake: When lawyer Goodwill is in the secret laboratory, he picks up a bottle that has "Jekyll and Hyde Juice" written on the label, but when we see him with the bottle in the next shot, the words have disappeared.