Continuity mistake: In the last fight scene, particularly during the close-ups of the fighters, you can clearly see in numerous shots that the auditorium seats are empty. This is contrasted with the earlier shots where it is jam packed as the fighters are entering the ring.
Continuity mistake: In the scene where Adrian is waiting for Rocky as he is returning home, she is going to surprise him with a gift, Butkus the dog. Rocky is standing about 25 feet from her so he has a good angle to see the entire porch. When she presents him with the dog, he acts surprised like he didn't see him on the side of the cement porch. Plus she is holding the dog leash in her hand. Rocky would have seen the dog immediately.Louis
Factual error: In more than one scene you can hear the sounds on a steam locomotive chugging and blowing the whistle. Steam locos disappeared by 1959, which is 17 years before this movie is set.