Continuity mistake: When Oliver's wife comes to see him in the dining room, you can see she is wearing frilly sleeves. But when she goes into the kitchen in the next shot, the sleeves have gone.
Continuity mistake: When Oliver gets stuck in the vent port, he has his arms tucked inside. When we see Stan climbing up a ladder to give him his bowler hat, Oliver has his arms outstretched.
Continuity mistake: In this 1933 Mickey Mouse short, Mickey dreams he is in a mad doctor's castle. He opens an inner door and finds a second door behind it. He then finds a third, fourth and fifth door. When a sixth door swings open and he is able to enter the mad doctor's lair, the other five doors have vanished.