Character mistake: In the "Casey At The Bat" sequence, the narrator says "The score is 4 to 2 with but an inning left to play." However, the scoreboard shows that eight and a half innings have been played, and only a half-inning remains.
Character mistake: In every scene George is with Mary, she never once wears glasses. However, when he meets her coming from the library after he was never born, she is wearing glasses. George is shown how he has influenced all the people in Bedford Falls over his lifetime, but having Mary's eyesight degrade to the point of needing glasses isn't one of them.
Character mistake: The score board during the game shows the Gas House Gorillas have the scores 10, 28, 16 and 42, for a total of 96 runs. But later on the announcer gives the score as "Bugs Bunny 96, Gas House Gorillas 95."