This may have been mentioned before, but...

When Michael shoots McCluskey, the first shot is in his throat, but the red dot indicating the second shot, to his head, appears at the same time.

When Sonny is machine-gunned, bullet holes appear on his car, then disappear, then appear again.

Ntra la porta tua lu sangu � sparsu,
E nun me mporta si ce muoru accisu...
E s'iddu muoru e vaju mparadisu
Si nun ce truovo a ttia, mancu ce trasu.