Continuity mistake: When Senator Geary talks to Michael in his Lake Tahoe office and the camera is on Michael there's an older couple (the woman is wearing a fur jacket) walking by outside. The camera cuts to Geary for a while, and when it cuts back to Michael the same couple is still walking by. (00:16:15)
Factual error: After the attempted murder of Frank Pentagalli takes place, as the shootout in the street continues a Mark II Jaguar is parked across the street. Not in 1958.
Visible crew/equipment: In the flashback scene shortly after young Vito has killed Fanucci and then joins his family on the front steps, a boom microphone is visible above and to the right of the steps.
Factual error: Corleone and Roth meet in Havana in Christmas 1958. The initial scene shows a panorama of a full street with people and American cars passing by. Among the cars we see a Jaguar Mk.2 in the opposite lane driving away. New Years day 1959 Batista flees the country and Fidel Castro takes over. The Jaguar Mk 2 wasn't introduced until late 1959.