Continuity mistake: When the seven dwarves run scared down the stairs and out of the door, Dopey pulls the handle of the door from the inside until it breaks out and falls away. The next scene when the dwarf opens the door, the handle is there again. (00:33:00)
Continuity mistake: A bird with a violin begins shooting off his bows like arrows, and they all follow the same trajectory and go over some flute dogs' heads. They don't duck in time for a couple of them and their wigs are taken off. The bows then fly and put the wigs on an elephant and a hippo, but at different angles. They should have been coming in at the same angle. (00:05:30)
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 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: 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: Goodwill captures four of the pigs and confines them in a pillory, a wooden framework with six holes. The head of each pig is sticking through one of the holes. After Goodwill captures Petunia, Porky enters the laboratory and discovers the pillory. Five pigs are now confined, and the sixth hole has disappeared.