Continuity mistake: After the failed attempt to drop a mace on Mr. Ginormous' head, the giant grabs Jack, Tom, and Jerry and taunts them. He then throws them onto the table and Jack's hat comes off and flies away from him. Shot changes angle to Jack trying to sit up and pop off at Ginormous and suddenly his hat is right next to him.
Continuity mistake: After seeing Mr. Bigley's car pull up, Jack takes off to inform his mom thinking they have a customer. As he is running up to their trailer, the window to the right of the door is shown to have the top part above the door. The as the camera cuts to a closer view as Jack begins trying to open the door, the window is below the level of the top of the door.