Continuity mistake: Curly's shirt is stained with clay, yet he hasn't been hit in the chest yet.
Continuity mistake: When Minnie Mouse falls down on the pillow whilst attempting to skate, the pillow bursts and covers Mickey with feathers. When Mickey goes off skating you can see nothing surrounding the pillow, but when we return to Minnie later on, there are now a lot of feathers around it.
Continuity mistake: When Beans the Cat puts the cat and dog into the piano, you can see there is a book in front of Oliver Owl. But after Beans closes the lid, we cut to Oliver and the book has disappeared.