Plot hole: Stewie gets out of the car seat and goes back to bed, leaving the blanket at the bottom of the seat. When they get to New York, Lois goes to get him out and realises he's gone. But when they started the trip the blanket was covering the entire seat to make it look like Stewie was still in it. So who ever "covered" him up knew he wasn't in the seat before they set off. (00:13:45)
Continuity mistake: After getting the uranium, Stewie places it in the time pad and then puts the pad in his jacket pocket. After being confronted by Hitler who promises to spare them if they sing a musical number, Mort interrupts them, and it's seen that he is now standing on the time pad.
Continuity mistake: After Conway Twitty finishes his song, the scene cuts back to Perter and his family at the kitchen table. Take notice that Lois is sitting next to the back door, and Brian is sitting next to the kitchen sink and window. Keep an eye on that kitchen sink, window and door, because it will be replaced by a yellow wall with the telephone now being closer to Lois. Later as Lois, Brian and Peter are discussing OJ Simpson, the sink, widow and door return.
Continuity mistake: In the part where Meg is asking Brian about God, and Brian answers he is an atheist, the camera pans out quickly, and we see an entrance to the kitchen with an air vent above it. Eventually the family discussion with Brian continues, and you see that the air vent is now gone.
Continuity mistake: Before Dr. Hartman delivers Bonnie's baby, he removes a small wheelchair and places it on a cabinet next to him. After delivering the baby, he makes a funny remark about Paula Poundstone, and then he hands the baby to Bonnie. Notice that the wheelchair and the cabinet are no longer present.
Continuity mistake: As Joe is waiting on Peter, Quagmire and Cleveland at the bar, take notice that he is holding a tray with two bottles of beer on it. One bottle is sitting behind the other in the close up shot of Joe. However when the shot pans out, you see that the bottles are side by side.
Continuity mistake: Toward the end of this episode, Stewie is at home in the living room talking to Rupert about how depressed he is about being alone. All of a sudden he hears his family come back home, so he gets up from the couch and runs to the window leaving Rupert on the couch. As soon as Stewie moves his head away from the window take notice that Rupert is no longer on the couch.
Continuity mistake: As Peter makes a comment on Jesus' joke, the screen goes into a closeup between the two of them. The potatoes on their plates change from a sandy yellow to white and the next time their plates are in view, the potatoes are back to their original colour. (00:11:33)
Factual error: In the park, Stewie and Brian are playing the "water pipes" like a xylophone. Trouble is, in order to get the tones they were playing, the glasses should have had different levels of water in them. If you look closely, all the glasses have the same level of water.