Continuity mistake: When we see the paper boy holding the newspaper, you can see that the paper is entitled "Extra", but when we see a close-up of the paper in the next shot, the title is now "Times Dispatch."
Continuity mistake: When Calvin Q. Calculus leaves his house when his wife says "You are going to regret it", the colour of the front door changes from dark brown to light brown between shots.
Continuity mistake: When Calvin Q. Calculus has invented the portable hole, he says "Eureka!" and you can that there is a beaker on the desk, but in the next shot the beaker has disappeared.
