Factual error: Milo gets out of the car to pump gas, but they are in New Jersey where pumping your own gas is illegal.
Continuity mistake: Nicole is sitting in a club with Irene's men at a table. The shot changes from a close up of her and the men, to a close up of Milo (with Nicole and the men in the background). After Nicole is finished talking to Milo on the phone you can see her hang up the phone in the background when the camera is on Milo and then she hangs it up again when the shot goes back to her.
Character mistake: In the scene where Stewart calls Nicole at the end of the movie, he tells her that he got a horse shot in the leg, when in fact they showed him getting the shot in his neck.
Plot hole: Milo and Nicole go to the club and ask for John. After failing to convince the woman that he works in the senate for Kansas, the woman looks at him and calls him 'Senator' but calls Nicole 'Mrs Boyd'. There was no mention any of their names (even though Milo's surname is Boyd). If the woman calls Nicole Mrs Boyd, she surely must know Milo and that Nicole was his wife.
Continuity mistake: When Milo is driving the car he sees a piece of black pond scum on Nicole's neck. He reaches with his right hand to pick it off while driving with his left hand. After the angle changes he is throwing the scum out of the car with his left hand while his right hand is on the steering wheel, without moving his hands. (01:06:35 - 01:07:10)