At the end, the detective takes the note from Jimmy's hand, but in the next shot, he is standing too far away from Jimmy to have been able to reach it.
When Mike is telling Jimmy to "Get out of my house" shortly after he shoots Danny, the scene shows the front door is closed and seconds later when the shot goes back to the door it is wide open.
About 0:38:00 Jimmy rams the side of the police car with the front of his own car. In the majority of the subsequent car chase, the front of his car is undamaged.
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 Jimmy is shooting his way into the bar the music playing is Fairytale of New York by The Pogues, but when the scenes change the verses are out of order.
The New York Post newspaper is dated Thursday, September 23, 1996. September 23, 1996, was a Monday.
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.
According to the mug shot of Jimmy, played by Liam Neeson, he is a about 172 cm tall (5ft 8inches). Jimmy is clearly taller than this, and in reality, Neeson is 193 cm tall (6ft 4inches).
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.
The 7 train does not run along Jamaica Ave, nor does it stop at 121st Street station.
The actual 121st Street station along the J line does not have an center island platform.
The car chase between Danny with the dirty NYPD officers holding Mike hostage in the back of their cruiser starts under the Manhattan Bridge but suddenly winds up under the elevated tracks in Queens. Such a car chase would take almost an hour sustain at that high speed.
Eddie's house is not under surveillance.
The hitman found an old photograph of Jimmy and his son at the lake. On the back of the photo, there was the name of the lake, but there are typically multiple (anywhere from 10 - 100) residences at large suburban lakes. How would the hitman find the exact lakehouse? Maybe he followed Jimmy or Michael, but then he would have already shot everyone.
If they are Albanian gangsters in the movie , they would not be speaking Serbian .