Continuity mistake: When Rocky leaves the Jewish mausoleum on his motorcycle, he has no helmet. When Rocky arrives at his statue, he is now wearing a helmet.
Suggested correction: So he stopped either at home or a store and got a helmet.
Revealing mistake: When Paulie throws the bottle at the Rocky pinball machine at the beginning of the movie, the glass smashes but the bottle doesn't, indicating that the bottle is an obvious prop.
Suggested correction: Liquor bottles are small and dense and much stronger against damage than a thin sheet of plate glass.