The set for the pilot is set similar but obviously different than the design of the following episodes; the front door exits out into a hall; that's clearly seen when Estelle makes her appearance. The makeup of the living room is a bit closer together than the set becomes and doesn't have as many doors off the main room like for the downstairs bathroom that Rachel uses in a later episode. The kitchen is the only set that remains fairly the same when the show moves into the series.
The back of Valerie Jones, who played Judy Winslow in the pilot episode, can still be seen in the opening credits at the dinner table scene. It remains that way until the end of the first season.
This actually applies to every episode after this, but since this is the first episode with the new living room I'll mention it here. I know that the house that is seen is stock footage, but it doesn't match the interior. If you look at the porch when someone opens the door, there are a lot of plants, and even a bench. That's not seen on the stock footage. Also, to go down the stairs, you would have to turn left. On the stock footage, there is no real porch. Also, how would someone drive into the garage in the back of the house? The back yard is on the same level as the rest of the house. Also, in the closing theme song when it shows the Winslows at the piano in the living room, the piano shouldn't be at the corner of the house. Remember, the piano was right by the kitchen, so if you go to the right, then you go into the kitchen, which clearly doesn't make sense. The piano should be on the side of the house, or located right next to the door. Also, the stairs to the left of the living room door shouldn't be there, because they go too far over. The exterior shot shows a window there.
The original cold open to this episode featured a scene with Judy, Laura, and Carl. After the original airing of this episode the producers replaced it with a new cold open to feature Steve Urkel tricking Carl out of his sundae, to make it look as if Urkel was on from the beginning. The first season DVD set uses the Steve Urkel version.
The original cold open to this episode featured Harriette telling Eddie, Laura and Judy to wash the dishes while she gets ready to go to a PTA meeting. After the original airing of this episode the producers replaced it with a new cold open to feature Harriette and Carl sitting at the table and Steve Urkel comes with a robe on saying he was taking a bath, to make it look as if Urkel was on from the beginning. The first season DVD set uses the original version.
When they are in the bathroom, he says to put your goggles on and then safety first and puts his googles on. Then when it shows him hammering the nail, his goggles are up.
When Carl was in the bathroom, he kicks something at the wall and then the mirror falls and you hear the glass break, but the mirror is still together.
When Rachel finally tells Buddy Goodrich her name he says that it's nice to meet her again. However, she did not tell him her name before and Harriette never introduced her.
If you look close enough to the left, notice that a curtain for the window falls in the scene where Harriette is talking to Laura on the porch.
Steve says that his parents names are Herb and Diane, but in the episode "Hot Wheels" Steve's mother calls the Winslows, and Steve says "What's up, Roberta?"
In this episode it is said that Carl's best friends are the Darnells, but later, in "Mama's Wedding", Stel says that Carl's best friend's name is Boby Johnson.
If the car couldn't start, most likley, Carl couldn't have let the window up (the car obviously had power windows and not crank) and couldn't leave the interior light on in the car. Also, they said they were on a dirt road, but what dirt road is a state road?
In conflict to the restaurant trivia piece. Two of those instances Steve (and Stefan) were involved, being that Steve took Laura there it was very likely he'd take people there in the future. And Laura was referring to their peers due to how expensive and formal the restaurant was, kids under high school age probably wouldn't go there. Carl and Harriet probably went there, or were recommended to the restaurant by Steve in the future.
Laura takes comfort that nobody she knows ever comes to the restaurant Steve picked out. However, in the episode "To Be or Not to Be," Steve and Myra, Carl and Harriette, and Laura and Stefan each appear in the restaurant.
When Carl is giving his toast in the kitchen, the shadow of a crew member passing off the set can be seen behind Judy's chair.
Laura goes up to bowl and Eddie coughs to make her miss. Then Steve goes up to bowl. In the rules of bowling, unless you get a strike, you always have two turns. Laura didn't take her second turn.
Steve is supposed to be a genius so how does he not know that you don't throw water on a grease fire?
In the first scene at Leroy's place, Steve Urkel (a waiter) walks out carrying multiple plates of food in his arms and one plate of French fries in his mouth to the customers. Wouldn't carrying a plate of french fries in your mouth be a major health code violation?!
Continuity: In this episode, we see Carl buying the ring and cassette from Steve but in season 9, we see that Steve is proposing to Laura and states that it is the same ring he kept all these years while playing the same cassette. How is this possible if Carl bought it from him?
In the episode "Torn Between Two Lovers" Eddie's girlfriend Jolene broke up with him, however in this episode they're dating again with no explanation.