In one of the first scenes where the two gunmen block the oil truck with their car and approach the truck we can see another car in front of the truck. After they throw the driver out of the truck and drive away, both cars are gone.
When the young salesman comes to in the back of the truck, his briefcase is next to him. In subsequent scenes the briefcase is nowhere to be seen.
The kitchen, where they tell the babysitter to go home, is not at all consistent with the supposed "mansion", they live in. Several other interior scenes appear to be shot in a different location, home, or set.
In the meeting with Abel, Joseph Mendelsohn is shown wearing a wedding ring. Chassidim and other Ultra-Orthodox Jewish men do not wear rings or other jewelry.
When the shot at the end goes into the tank, it is at an angle, and the likelihood of a pistol round penetrating 3/4 inch steel is virtually impossible, regardless how closely the shot was fired. Also, Abel plugs the leaking oil with a handkerchief; this is also nearly impossible from a tank this size.
In the chase scene that goes onto the subway platform, as Morales jumps onto the subway, the "doors closing" warning chime can be heard in the background, but the subway cars in the scene never had the audible warnings. The only indication of the doors closing on the older cars was the conductor announcing, "watch the closing doors".
When Abel and Andrew are delivering Julian to the police, both Abel and Julian get out of the car. However, in the next shot Julian is still in the car talking to Andrew.
Just after Abel and Anna close on buying the business property at the end of the movie, they walk and look at what they just purchased. One of the two oil tanks they pass has a date of 12-15-93. The movie took place in 1981.
In the opening scene where the Standard Heating Oil truck pulls up to the toll gate, modern-day cars can be seen in the interchange lanes.
NYC tollbooths in the 1980s had change baskets attached to every booth.
In the very opening running scene, modern cars can be seen parked in several driveways. Also, near the end of the movie, when Abel talks to Arnold in the barbershop, modern cars can be seen driving on the street behind the parked period correct trucks.
When the young salesman goes out his first day, there's a shot of a residential street. Several houses have modern satellite dishes attached to their roofs (like dish or DirecTV). There were no home satellite dishes in 1981.
The car that Abel drives throughout the movie is a Mercedes Benz W126 Coupe, which was introduced to the Market in 1981, the year the movie is supposed to be happening. The actual car driven already has the modified side bumpers and alloys introduced only after 1983.
When Abel goes to Lefkowitz for a loan and Lorraine asks him how much he needs, he replies: "A million and a half dollars." In the script, he answers $500,000. This was spoken during the shoot and the newer figure changed in post-production. The audio/visual mismatch is visible.