Continuity mistake: After they almost get run over by the man on the motorcycle, Jack receives a phone call. He answers with his left hand on his left ear, then it cuts and it's in his right hand and his right ear. It switches back in the next cut.
Visible crew/equipment: When stuntman Mike and the girls cars come back together after being separated by a pond, the shadow of a car-mounted camera crane is visible in the left bottom corner. (01:44:00)
Continuity mistake: When Nancy defuses the bomb, leaps into the air and falls down, her head is rested on her arm when she is lying on the floor (in the first scene). In the next scene, her hands are both together and her head is on the ground. (00:50:50)
Visible crew/equipment: Several times in the movie you can see a stunt double for Donnie Wahlberg, like when he tries to hang himself. Art runs over and there is a wide shot focusing on both of them. No slo-mo required, but you can see it's a stunt double.
Other mistake: Eddie comes to see Tom at the bathroom clean-up job and convinces Tom to confide in him. Eddie tells Tom that he'll, "See what Wallace knows". There is no character named "Wallace" - he was supposed to say "Vargas", the investigator on the case. The subtitles correctly reference Vargas.
Plot hole: Spoiler! We find out that "Rogue" is actually Tom Lone, who killed the real Rogue and destroyed his face to prevent identification, then had plastic surgery and went underground to get revenge. But how is the body never identified? Lone was a cop, they'd have blood type, DNA etc. on file, which would have proved the body wasn't his.
Continuity mistake: In the scene where Dakota is having sex with Aubrey's boyfriend, it specifically shows that her bra is off. Once they finish, and she is getting off of him, she is covering her chest with the sheet. When she does this, her side isn't covered and you can that she is now wearing a black bra.
Continuity mistake: In the railway station where 47 is being followed by the FSB, Interpol and the older agent, you see the older agent running down the ramp to platform 9 after 47. His jacket is flying up in the back, and there is no weapon visible. When he stops running, he reaches behind him into the waistband and produces a handgun with a silencer.
Revealing mistake: During the heavy snowstorm, the telephone wires are still, even though it's a blizzard.
Other mistake: When Jennifer and Gary are scratching the messages to each other on the painted glass, the glass is painted black on both sides so they wouldn't be able to see each others scratchings as the paint on their side would cover the marks the other was making.
Factual error: Firearm issues abound throughout the film. The British detectives (who all seem to be armed, rather than a low proportion of AFO (Authorised Firearms Officers) as in real life) are shown carrying Beretta pistols, even though the Metropolitan Police issue the Glock 17. The SFO (Specialist Firearms Operations) officers are shown carrying MP5 submachineguns, which is accurate, but fitted with cheap toy-shop lasers. Weapons handling is poor throughout, with chickenwing syndrome particularly prevalent. Weapons carriage also appears geared to look "cool" rather than realistic; shoulder holsters - which practically everyone wears in this film - are rarely used for concealed carry in reality.
Visible crew/equipment: When Jamie leaves his father's house to meet Henry at the theatre, a member of the production crew can be seen standing behind a bush in the garden as his car reverses.
Suggested correction: It's the gardener seen earlier in the film when Jamie first arrives.
Continuity mistake: The "Power Play" scene when Eric and Hanssen are in the car after a cancelled meeting (13). With Eric's line, "There's construction on E Street," the Kennedy Center appears behind his head, but in the next shot of him ("Sir, I'm SSG.,") the Kennedy Center shows up again, this time farther ahead of the car. (01:05:55)
Factual error: In the scene when Kale uses the lamp, taking off its lamp-shade, to see what's inside the hole, he points it in there. The lamp, actually, shouldn't illuminate the wall in one point creating a circle like a flashlight but wholly lighten the larger area. (01:30:00)
Continuity mistake: During the complete car-bomb chase sequence towards the end of the film, Michael Clayton's car is shown in one shot without its lights on. All the surrounding shots in the scene have both cars with their lights on. This is also a slightly revealing error because it shows that they actually filmed these sequences during the day using neutral density filters. (01:41:15)
Visible crew/equipment: During the scene where Harrison raises his fist to Rowena, there is a brief moment when you can see what looks like a shadow of a boom mike and crew member behind Rowena's head on the ground behind her. (01:16:35)
Continuity mistake: As Mike scrolls through the microfilm, we see his view as the pages scroll from right to left. The shot then reverses to show his face through the scrolling film, but while the film is now properly reversed, it's still moving right to left in our view. But this reversed angle should show it moving left to right. (00:12:05)
Visible crew/equipment: In the scene where Doyle is talking to the helicopter pilot at the park, you can see another pilot on the left side of Doyle's head for a split second. (01:14:50)
Continuity mistake: When Carter and Lee are fleeing the motorcycle thugs in George's cab, the driver's seatbelt is hanging unused. In the next shot, George is suddenly wearing his seatbelt. (00:34:55)
Factual error: There is a scene near the beginning of the movie when the mist has just begun. A firetruck roars by, and has Caddo Parish Fire Dept. on the side. This movie is set in Maine. Louisiana is the only state with parishes. All others, including Maine, have counties. (00:10:50)