Other mistake: In the scene where Jimmy and Henry try to strangle Maury with the telephone cord, the handset is off the hook, but the telephone still somehow rings.
Other mistake: Even though this is a fictional event of how Billy Batts was murdered, he was a made man in the Gambino Crime Family. So, it doesn't make sense for him to have a party of him coming home from prison at a rival family's establishment, meaning Henry Hill's club, which was a Lucchese Crime family hangout. He would have had the celebration on his own turf, around his own family.
Suggested correction: While there is no way to prove how factual it actually is, this is almost exactly the way the real-life Henry Hill told the story in the mafia memoir, Wiseguy. The only differences being that Batts was not killed that night, but a couple of weeks later, and Henry did not own the club, Jimmy did.
Well, that isn't at all the disagreement here. My only concern was, why was a Gambino made man having a party at a rival family's establishment and not on their own turf? That's the blooper here.
Other mistake: When we see the shot couple in the pink car, there's blood spatter inside the windows and windshield, so that means the windows were up when they were shot, and they were shot in the car. It makes no sense that neither the windshield nor the windows are broken. If Jimmy shot them from the front, he would've had to have shot them through the windshield. If he shot them from the side, he would've had to have shot them through the window.
Suggested correction: This one is pretty weak. Jimmy knew them. He could have easily walked up to the door and opened it, as if to admire the car, as if to talk, or for any other reason, shot them, and closed the door.
Other mistake: When Tommy kills Stacks, after he leaves the apartment, they re-enact the murder from a different camera angle in slow motion, where we see Tommy's face. Right before Tommy starts shooting, we can see blood stains on the wall already.
