When Drew Preston is walking with Billy Bathgate and takes his hand, the close-up shows her hand is on the front. In the next shot, her hand behind his and facing to the rear.
When Billy and Becky are first seen on the roof in long shot she is exhaling smoke; in the close-up immediately after, she doesn't have a cigarette.
The film portrays Schultz as a middle aged man, played by then 54 year old Dustin Hoffman, but in reality Schultz was on 34 years old at the time of his death.
The film appears to show an extended period of time between Bo Weinbergs murder and Dutch Schultz death. In reality, Schultz only lived about a month longer than Weinberg.