Continuity mistake: As Charlie enters the bar Dennis is writing a sign that says: "Carmine's A Place for Steaks." A shot later and the sign is unfinished, with the words, "Carmine's A Place..." The words "for Steaks" are not on the sign.
Other mistake: In the opening of this episode the screen reads "3:50pm On a Wednesday." When Gino (Frank's Brother) is reading the letters meant for Shadynasty, he says "Meet me at the airport, Friday, at 5:00, Terminal C." The gang and Gina then go along to the airport that very afternoon - a Wednesday - to try and meet Shadynasty and get her and Frank back together. And of course she is there, despite it being a Wednesday, not a Friday.
The Gang Goes on Family Fight - S10-E8
Continuity mistake: When Dee hits the buzzer, it completely disconnects from the table and flies some distance away. In a panning shot shortly afterward, the buzzer is hanging from the table by a cable. (00:11:55 - 00:12:35)
Dennis and Dee Get a New Dad - S2-E10
Continuity mistake: Dennis walks up to the computer to see the guy claiming to be their father carrying nothing, he puts his empty left hand on the bar, but when the shot switches he is holding a coffee in that hand. In the shot right before the opening credits the coffee is gone again. (00:01:00)
The Gang Runs for Office - S2-E8
Continuity mistake: When Sweet Dee is talking to the comptroller. The comptroller's wife throws the beverage into Dee's face. In the next shot the beverage is full and in the original spot. (00:18:15)
The Gang Exploits the Mortgage Crisis - S5-E1
Continuity mistake: After Dennis, Charlie and Mac kick apart the family's front door, the amount of damage to the door decreases significantly when Frank begins questioning the lawyer.
Revealing mistake: During the training montage, right as Mac is about to smash the bottle over Charlie's head, you can see Charlie stop what he's doing about a half-second before being hit, and brace himself for the impact, despite not being able to see it coming. This is confirmed on the DVD commentary.
Reynolds vs. Reynolds: The Cereal Defense - S8-E10
Continuity mistake: During Mac's presentation of science being wrong sometimes, the "bitch" labels move around after he slaps them on.
The Gang Reignites the Rivalry - S5-E12
Continuity mistake: When Dee is practicing cup flipping in front of Mac and Charlie, all the cups are right side up. In the next shot one is lying on its side without her knocking it over.
Mac and Dennis Break Up - S5-E9
Continuity mistake: After Mac throws water on Dennis, the size of the water stain on his sweater changes throughout the scene.
Mac and Dennis: Manhunters - S4-E1
Continuity mistake: In the beginning when Frank takes the plates of meat away and sets them on the bar counter, the newspaper that Mac lays down changes pages during various shots, the items on the plates shift too sometimes.
Bums: Making a Mess All Over the City - S3-E14
Continuity mistake: When Frank, Charlie, and Dennis are in the cop car at the red light, they're on a one-way street, with cars parked to their left (facing the same direction as the cop car). However, when it cuts to Frank, we see a car drive by in the opposite direction, and the parked cars are gone.
The Gang Gets Held Hostage - S3-E4
Continuity mistake: When Frank and Charlie are coming out of the vent and onto the roof there is no gun taped to his upper back, he walks up to the Mcpoyles and a gun is magically taped there. (00:19:40)
Continuity mistake: The three selects that Dennis shows Dee, the guy with the black tank top and sunglasses is all the way to the left. When the shot switches the guy is all the way on the right - this is the guy Dee says is "One big chin." (00:06:00)
The Gang Gets Held Hostage - S3-E4
Revealing mistake: When Liam is stabbed in the arm, as he turns around to walk away, you can see the outline of his real arm wrapped behind his back, under his robe for about one full second, revealing that the arm he was stabbed in was a fake prop-arm.
Visible crew/equipment: During the scene where Dennis and the Waitress, Mac and Dee successively walk into the back office to talk to Charlie near the beginning of the episode, in some of the shots, you can see outside the office door, and you can see the top of the set has no ceiling, and even see part of a stage-light.
Continuity mistake: While Mac is holding the picture of himself to Dennis & Dee, towards the end of the scene he is holding the picture with one finger around the middle on the top edge. Dennis then says "You're going to hell". The next shot he is holding the picture by its side with two fingers.
Charlie Goes America All Over Everybody's Ass - S2-E9
Audio problem: When the Vietnamese man is playing Russian Roulette in the end, a few seconds after picking up the gun, he moves his thumb and we hear the gun cock. However, you can see that he didn't actually cock the gun, as his thumb never came into contact with the hammer while moving, hence the sound was a phantom sound.
Paddy's Pub: The Worst Bar in Philadelphia - S4-E8
Continuity mistake: At the very end, while the gang is reading the new review and then talking about how their names weren't mentioned, a hammer appears on the bar between them, only to disappear a few shots from the end; Charlie then retrieves it from under the bar as they leave.
Mac is a Serial Killer - S3-E10
Plot hole: Early in the episode, it is mentioned that the serial killer is murdering "Young, attractive blondes", yet at the end of the episode, when the gang finds all the severed heads in the killer's refrigerator, almost none of them are blonde or young, contradicting what had been previously established.
