Sylvester Stallone originally planned to make the effects of Rocky's brain damage much more visible and painful to see, but altered these plans after watching a few days of footage because the sight of Rocky like that was "like seeing your favorite dog with dysplasia."
During shooting, John G. Avildsen felt that cinematographer Steven Poster was over-lighting many scenes. He told Poster he wanted the film to look more like Rocky (1976), in which James Crabe often used a single spotlight to light an entire scene (such as the opening boxing match). Poster told Avildsen that the original film "looked like a cheap documentary". Avildsen smiled and said, "Exactly".
Sylvester Stallone originally toyed with the idea of killing Rocky off at the end of the film. The plan was that Rocky would die in an ambulance on its way to the hospital with Adrian by his side. At the hospital, she would have announced to the world of his passing and his spirit would live on with a final flashback of the famous scene of him running up the steps. Stallone ultimately abandoned this concept and rewrote the ending.
In an interview with Jonathan Ross, Sylvester Stallone was asked to rate each of the "Rocky" movies out of 10. He gave this movie zero.
This is the first movie where Rocky's real name, Robert, is used. When Rocky first meets Tommy Gunn, as George Washington Duke pulls up in his limo, Duke says "Mr. Robert 'Rocky' Balboa!"