Continuity mistake: At the convention when we first see Roger and Hayley, they pass a booth that says Costume contest registration. There is also a few people around, a poster and a movable wall. The very next shot is more of a close up of the two and the background has changed dramatically. There is now about 4-5 different stalls behind them and no sign of the previous one or the poster and wall.
Continuity mistake: In the scene where Francine says she used to be friends with everyone in the block, there is a cutaway of a previous neighbor couple called the McLearys. After the cutaway, keep an eye on Francine's coffee mug. The mug keeps changing position on the table between shots.
Continuity mistake: In the pilot episode, during the breakfast scene, there are five donuts in the box in front of Roger before his chair breaks. When he takes one from the box, there are eight. When Francine takes his donut away, there are five in the box again.
Continuity mistake: Steve, Hayley and Francine all stand next to the door when Bullock arrives. They are all standing right next to the door in the shot where Stan adjusts their clothes. But they have magically moved a foot away from the door in the following shot where Stan opens the door.
Continuity mistake: Just as Bullock rings the doorbell, Roger oozes gunge from the left side and right side of his torso. The gunge from the right side goes on the couch and the left side goes off screen in a direction towards the door. Yet when Stan answers the door, no gunge is visible on the floor anywhere.
Factual error: Steve and Roger make a prank phone call to Tony Blair at 4:30 AM GMT during sunset in Virginia (EST/EDT); because of the 5-hour time difference (4 hours during Daylight Savings), it would be 11:30 PM or 12:30 AM in Virginia, which would be nighttime.
Continuity mistake: After Steve accidentally jabs the wood burner into Stan's penis, he screams and a avalanche occurs. Then when Stan screams a second time due to putting the cream on his penis, the avalanche happens again but the same amount of snow is on the mountain even after a load already fell off it.
Continuity mistake: When the bus driver finds Roger, the Dignity Towers Retirement Home bus is only a few feet away from them. But in the shot where Roger says "How do I get home? How do I get home?", there was no sign of any bus for many many meters. As if the bus just appeared out of nowhere.