Sonny's Missed Punch

Big deal, so the punch was way off. Do you really think actors ACTUALLY punch each other in the body or face? It never happens, unless they want a LAWSUIT.

Here's an explanation of sorts from the book "The Annotated Godfather" by Jenny M. Jones:

In the most famous technical mistake of the movie, now known as The Miss, one of Sonny's punches misses Carlo by a mile – despite the clear audio of contact. Coppola laments that the gaffe was due to film's squeezed budget: "At that point we were just rushing, and it turned out that the best take had this one miss. Today they could fix it with digital effects."

if we're going to mention this, think we've also got to mention Barzini's stunt double when he gets shot. Goes tumbling down those stairs like an acrobat, after a couple of rolls the hat comes off and you can see the longer hair flopping around.
Could easily have been avoided if he'd just dropped dead on the top step, but I suppose it looks better and more dramatic to see him rolling down the stairs

I never noticed it