When Shane is driving in his Camaro Z28 to his father's home to drop off Christmas presents, a New York City cab can be seen in the rear window. The cab is a 1997 Ford Crown Victoria.
The plot of the movie takes place in the mid-late '70s, yet a 1990's Chevy police car is shown is a few scenes.
There is a shot of a milk carton on the breakfast table at Shane's house. The carton contains a "Nutrition Facts" label that didn't exist until 1994.
On the invitation for the New Year's Eve party, the date is incorrectly typed as "the thirty first of December Nineteen seventy-eight..." The date should be Nineteen seventy-nine.
In the first scene, when Shane looks across to the Manhattan skyline, the MetLife building is visible, with "MetLife" in lights across the top of it. In the 1970s, this building was the Pan Am building with "Pan Am" in lights across the top.
Patrons casually called Studio 54 "Studio" instead of "54".
When Shane is bringing Christmas presents to his father's on Christmas Day, the radio station in his car is giving the stock market report for the day. The Stock Exchange is closed on Christmas Day. There would be no market update.
In one newspaper clipping towards the end, the word "survivor" is clearly misspelled as "surviver".
Many of the newspaper articles that are shown quickly are not the actual articles that match the headlines. The New Yorker article about Rubbell's arrest begins accurately, but the main body is an advice column. Two articles have identical copy. Some articles have blatant writing errors, such as misspelled words, missing hyphens, uncapped letters, etc. One article calls the Drug Enforcement Administration the "Drug Enforcement Administrative."
When the IRS shows up to raid 54, the wide shot shows two unmarked police cars with red lights flashing on the dash. Then a tight shot shows an agent climbing out of a car and the light on the dash is blue.
Early in the film, Shane's hair is shown with a short style before he actually cuts it.
When Shane is confessing to taking the money to Steve the wad of cash moves on and off the folder.
Obviously, in editing, someone erroneously placed the New Year's Eve invitation close-up just before the Christmas party. Some considerable time later, there was a totally separate New Year's Eve Party and that NY Eve invitation close-up was undoubtedly filmed to appear just before it, not Christmas.
When Salma Hayek is teaching the dance class, she refers to Breckin Meyer's character as "Breck", even though his character name is Greg Randazzo.
The song, "Let's Start the Dance" by Bohannon, played in a 1979 scene, was released in 1978.
Some of the lighting equipment we see is from HighEnd Technologies (Studio Color, Studio Spot and Cyberlight) which was not available until the early-'90s.
When Shane and Julie are bowling, Shane knocks down 8 pins including the 7. He then tells Julie he is going to to get the "7/10 split". When the camera shows the lane again the 7 pin is once again standing.