Continuity mistake: Just after the guests have found Muriel, there is a shot from outside the manor where we can see Quagmire's car at the back of the rest of the cars. But in the next overview shot of the manor, Quagmire's car is now in front of a red car.
Continuity mistake: When everyone is in the dining room at the dinner table, the order of where everyone sits changes between shots. In all moments where it shows everyone sitting, the order is Priscilla, Derek, Jillian, Mort, Muriel, and Carl. But in one shot, the order is Priscilla, Derek, Jillian, Muriel, Mort, Carl.
Continuity mistake: When Derek Wilcox is killed and on the ground, he is on his front with his head turned. He got hit above his right eye and blood is coming from underneath him, but after everyone else arrives outside, he is on his back with the wound above his left eye and blood is all over his face.
Continuity mistake: When Brian and Stewie arrive in Leonardo's atelier we know that they are in Florence for two reasons: because of history and because we see Palazzo Vecchio (which is in Piazza della Signoria, in Florence) outside the window. Then when Stewie and Bertram are fighting with Leonardo's flying machine the city of Florence is wrongly represented as if it was Venice, with the see, the lagoon and the canals.
Continuity mistake: When Peter returns home from being hyped up on Red Bull, he has numerous cans in his arms. When he sees Stewie he immediately drops the cans on the floor but when the camera pulls back as he sits down with Stewie in his lap, the cans of Red Bull are nowhere to be seen.
Continuity mistake: When Franz Gutentag falls off the step towards the end of the episode, Herbert is on the porch of the house and reaches out to him. When we see the shot of Gutentag falling in slow motion and the birds fly away, there is no sign of Herbert on the porch.
Continuity mistake: When Peter is eating dinner with Lois and her parents, on his plate there is mashed potatoes and meat loaf. Peter shovels potatoes in his mouth then spits them out all over the table. When his plate is shown again, the meat loaf has disappeared from the plate even though he didn't touch it.
Continuity mistake: When Carter destroys the bench after being the first contestant out of wining the old dirt bike, in the digger he backs off screen and you hear a crash and a car alarm, but when the shot is widened you see two cars where he backed into and both are undamaged.