After the moment when Jimmy answers the phone while watching the Rangers - Devils ice hockey match, you can distinctly hear the squeaking of sneakers coming from the television to indicate that there is a match going on, but there are no sneakers in ice hockey.
In the security screens at Shawn Maguire's place. When Jimmy watches him running, the date showed is 2014, December 1(the number next to the 1 can't be seen because is blurred). The scene is supposed to take place after Christmas.
When they find the 2 bodies in the limousine, they say "187 in the suspect vehicle." This is referring to California Penal Code 187 as a homicide. In New York, the Penal Law for a homicide/murder is 125, therefore they would not be using the code 187. LAPD often uses this code but the NYPD does not.
After Detective John Harding says, "For five years I have been chasing this son of a bitch, this gotta end tonight," there is a shot of the two dead bodies in the car and one of them closed his eye a little because of the flashlight.