When Frank says "Wanna take that knife away from my balls?" Marvin withdraws the knife he is holding to Frank's crotch. We hear a metallic sliding sound as if he's pulling the knife out of a sheath, but the knife is touching nothing.
(at around 16 mins) After making the call on the pay phone, Parker's character pronounces the name of the city in Alabama the same way one pronounces "mobile" phone. The city is pronounced "mo-BEEL." This is surprising, as Mary-Louise Parker is from South Carolina and the pronunciation of Mobile is widely known in the South.
When Frank, Sarah and Marvin are waiting in the hangar. In the long shot showing all three, Marvin is holding his stuffed pig by the tail and the legs are toward the camera. In the closeup seconds later the back of the pig is towards the camera.
After they exit the CIA building and enter the ambulance, there is a clock behind them showing 9:45 as the time. After they are gone from the place and are traveling on a highway, another shot shows the clock with the same exact time as before.
After Moses inserted the syringe into the gunman's neck and he has fallen down, it tilts to the right. Then, while the grenade is exploding in Moses' house, the dead gunmen with the syringe in his neck can be seen. Now it sticks upright in his neck.
When Marvin grabs the woman at the airport in Alabama, he's holding the stuffed pig in his right hand. A second later, he pushes her against a wall and he suddenly has a pistol in his hand and the pig tucked under his arm. Also, he cocks the pistol, but a shot or two later it's uncocked again.
When Frank Moses enters the deep file room under the CIA headquarters he kicks a hole next to the door and opens the lock from the inside. When he opens the door and is greeted by Henry there is no damage next to the door on the inside wall.
When Cynthia Wilkes brings hostage Sarah to the limo, Cynthia enters the limo from the right side after Sarah, sitting her on the right side. When the limo arrives at the power plant, Cynthia exits the car first - at the left side.
When Ivan and Frank first meet, Ivan proposes a toast to the love of his life, Veronique - but we later learn her name is Victoria. Seems an odd pet name to use, not to mention that we also find out his pet name for her is "Bunny".
When the outside of the hotel in which the VP gives his speech is shown, you can see a large Canadian flag. This is because even though the scene is suppose to take place in Chicago, the location is The Royal York Hotel, located in Toronto, Canada.
Marvin lives in an underground bunker in Florida with a vault. Not only is there no explanation as to how he managed to install a vault, but also very few houses or buildings in Florida have basements due to the high water table.
When the team traps the Vice-President's group in the parking garage, Victoria (Helen Mirren) is firing a 50 caliber machine gun at the group to keep them pinned down. An ammunition can is visible hanging off the weapon's left side. The armor-piercing ammunition readily pierces the vehicles.
The 50 caliber weapon is a belt-fed machine gun. Its large ammunition (5.45" in length) is usually fed from an ammunition can weighing 35 pounds and holding 100 rounds. The weapon at the sustained high rate of fire shown would be firing 450-550 rounds per minute, requiring it to be reloaded with a new can about every 13 seconds.
Before and after the VP's security team flanks the weapon and discover it is unmanned, it has been firing for at least 30 seconds without being reloaded. The armor-piercing ammunition would not only have easily penetrated the vehicles but the people hiding behind them.
When Joe is introducing Victoria to Sara He says, "she is an artist with an RPN", some might think this is a mistake thinking it should be RPG. Others might think, because she is dressed in white and is going to extract Frank's bullet, that she has an "RN" or that it is something like "LPN" ("RPN" would be 'Registered Practical Nurse'). It is probably not a mistake. When referring to RPN and "being an artist with an RPN" they are most likely referring to a series light machine gun (Ruchnoy Pulemyot Nikonova) similar to an RPK.
Frank wakes up at 6:00 in the opening scene (according to the bedroom clock). It is supposed to be Christmas time. At that time of year (in the USA) it would be dark out at 6:00 (a.m. or p.m.) yet there are signs of daylight in his unlit home.
The Plantronics hands-free headset that Sarah uses in her office has a red indicator light on the end of the microphone boom. The light is supposed to be off when the phone is not connected, flashing when the caller is on hold and constant-on when connected normally. However, every time Sarah is shown talking to Frank, the light is flashing, indicating that the phone is actually on hold.
In the first two aerial shots of the hotel in "Chicago" where the Vice President is appearing, you can see the hotel sign reading "Fairmount "Chi Cago" with "Chicago" being split in half. That's because they had to cover up the real name of the hotel, the "Royal York" which is where they filmed in Toronto.
The goof item below may give away important plot points.
When Frank kidnaps Sarah Ross and she is in the back seat her hands are tied in the front which she keeps bringing up to her chest. She can easily reach up and pull the tape across her mouth but she keeps yelling beneath the tape.