When Nicky is at his father's home he is cooking eggs. When he brings the eggs over to the table he has the egg beater and then when the camera angle changes he has a spatula. This goes back and forth a couple of times in this scene.
When the camera pans the Red Sox locker room, showing the hung up jerseys, the jerseys have Mitchell and Ness tags on the collar. Mitchell and Ness is a producer of historic and vintage jerseys. In 1986 the MLB uniform manufacturer was Rawlings.
While watching the beginning of Game 6 in the bar, Ron Darling appears to be the Mets pitcher. Ron Darling started Game 7, Bob Ojeda started Game 6.
Across the street from the theater showing Nicky's new play, there is a poster for the musical, Brooklyn. The musical opened on October 21, 2004, the night after the Red Sox won the ALCS on the way to winning their first World Series since 1918.
A fan is seen wearing a Mets jersey, with an underscore under the word METS. The underscore was put on Mets uniforms in the early 90s.
Articulated buses in NYC did not exist in 1986. They appeared in revenue service in 1997.
In one of the taxi/traffic scenes, a passenger in the car behind Michael Keaton's character is out of the car looking to see the cause of traffic. The passenger is an Orthodox Jew. However, this movie takes place on a Saturday (10/25/86), the Jewish Sabbath. An orthodox Jew would not be allowed in a car on Sabbath.