Continuity mistake: When Barney asks Fred if he could have 25 cents for a sandwich whilst practising their ventriloquism act for "The Ed Sullystone Show", you can see Barney has his left arm on his knee, but when we see a close-up of Fred in the next shot, Barney's left arm is missing.
Continuity mistake: When Barney shows Fred the ad in the paper about new novelty acts for "The Ed Sullystone Show", the ad says "Apply Bedrock Broadcasting Co" at the bottom. When we see Fred and Barney in the queue with the other applicants, the station is now called "Bedrock Television Company."
Continuity mistake: When Fred tells Wilma that he is stopping inventing at the end of the episode, he pours the remains of the reducing formula out of the window into Dino's bowl and Fred has a glass in his left hand. When he hears Dino at the front door, the glass has gone.