Factual error: Towards the middle of the film,Pacino and Depp are walking downtown, there is alot of traffic and some of the cars are "post 1978" model . One in particular caught my eye, which was a mid-80's Ford Taurus (even the model of the car didn't exist in 1978).
Continuity mistake: When Depp and Pacino are in the bow of the yacht Depp got from the FBI, Depp puts his glass on the rail of the boat and it is in shot. In one shot of Depp the glass is gone and the next time you see Depp its back.
Visible crew/equipment: In the scene where the two are crossing the bridge in the car, the camera crew can be seen several times as reflections in the windscreen when the shot changes to outside the car.
Continuity mistake: When Pacino asks a guy in a barbershop about Depp, the guy is being shaved, and the shaving foam is only on his cheek, but when he's at the doorway calling to Depp to come in the barbershop the foam reaches his temple, then back inside the foam is only at his cheek again.
Factual error: When Johnny Depp and Al Pacino are driving in the car (I believe it's the first time Depp drives Pacino around), they pass an MCI billboard - the one that continually updates the figures as to how much money you'd save if you had MCI long distance phone service. MCI didn't exist in 1978.
Continuity mistake: In one scene where the men are in Florida, there's a equence of Donnie calling from Miami to NY and it's cold and snowy there, then cut to Sonny in Miami reading about John Wayne's death, which occured in June of '79 (hardly snow time), then back to Donnie on the phone with his wife in NY.
Factual error: A group of guys are walking into a hangar at some airport. When they are walking into the door you can see a jet moving behind them. It is a Continental Airlines jet with their new Continental logo on the tail. I believe they updated it in the last two years. The movie was set in 1978 and this logo obviously wasn't on the jets back then.
Continuity mistake: When Depp is at Pacino's house and he is about to leave but still sitting down, Pacino is wearing a ring on each of his hands, but the one on his left hand disappears in the next scene.
Factual error: When Depp makes a phone call to his wife on a pay phone, the price of the phone call - $.25 - seen on the phone. Phone calls didn't cost that much in 1978.
Continuity mistake: Right after Nicky gets whacked, Donnie and Lefty are in Donnie's car arguing. They show several shots of the outside of the car, with some kind of camera rigged on the driver's rear side of the Caddy. This Caddy however looks different than Donnie's regular Caddy. The paint is faded and some of the body work is very crooked. They probably just found a junk Caddy to mount the camera on.
Continuity mistake: When the guy is vouching for Donnie at the barbershop, he and Lefty walk out of the barbershop and the windshield wipers on the Lincoln that Donnie is sitting in are off, and so is the car. The shot changes and the car is on and the wipers are wiping. Then the shot abruptly changes again and the car and the wipers are off once again.
Continuity mistake: Beginning of the movie, in the scene where Donnie comes by Lefty's for Christmas. As Lefty, Donnie and Annette are all in the kitchen, the wide shot shows them all with Lefty cutting the chicken on what is a pass through counter, with the stove behind him. The next shot shows the reverse angle with Lefty now at the stove with the counter behind him which now is closed in with a wall behind it.
Factual error: In the airport scene, the Burlington Air Express plane being towed is marked Burlington Northern Air Freight, Inc. (BNAFI), a subsidiary of Burlington Northern Railroad. In 1982, BNAFI was acquired by the Pittston Company, which later became Brink's. In 1986, BNAFI changed its name to Burlington Air Express, which is outside of the movie's time frame of 1976-1982.