Visible crew/equipment: You can see the microphone mirroring in the window of the car, when the two agents are leaving the taxi in Milan. (00:29:50)
Continuity mistake: The picture from the security camera, which shows the assassin leaving Milan, says it was on 24th of November 2008. The picture at JFK Airport is dated 24th November 2007. (00:52:10 - 00:54:45)
Factual error: If the two snipers were placed in the same building right on top of each other, and as far away from the target as we see, the difference in the angle of the two bullet trajectories would be very small. The difference shown by the plastic sticks would - at that long distance - mean a huge difference in height.
Continuity mistake: In the beginning of the movie, a man gets out of a car and walks toward a street while talking on a phone; he then starts to grab his upper left arm while vomiting. Before he falls to the ground, notice that there is a very noticeable amount of vomit on his chin. In the next shot his chin is almost spotless. (00:03:10 - 00:04:05)