When interviewing Jerry (Jerry Seinfeld), Sharon's (Paula Marshall) zipper on her top can be seen moving up and down between different shots.
When Kramer (Michael Richards) is talking to Jerry (Jerry Seinfeld) about the article, Jerry can be seen shaking his head. When the camera angle changes though, he isn't shaking it.
When Sharon first enters Jerry's apartment, George is drinking out of a bottle that switches hands between shots.
When Kramer is giving Jerry his present, Jerry's hands alternate between having his phone in his hand to not having it and then being folded, between camera shots.
A two line phone needs two phone lines to work. What Jerry is doing could be accomplished with call waiting.
When George is visiting his mother in the hospital, the male nurse enters the room and gives Estelle's roommate, Scott a sponge-bath. U.S. hospitals do not have "coed" rooms, and Estelle and "Scott" would never be hospitalized in the same room together.
George's mother says she had to call the super (aka apartment superintendent) to help her when she fell and threw her back out. In later episodes, it is established that the Costanzas have long lived in a house in Queens.
In one of the scenes taking place in Monk's Restaurant, a Marine in his Alpha Uniform (green with red-backed chevrons) approaches Jerry & George, thanks them for "coming out", and says he's going to do the same.
But in the Closing Credits, he's listed as "Anthony Mangano -Sailor" .
The second line on a two line telephone would not work unless a second telephone number was acquired from the telephone company.
In the end, how does George enter Jerry's apartment without anyone buzzing him in? He barges into the apartment without Jerry buzzing him in.
The article refers to George (Jason Alexander) as "Costanza," but Jerry (Jerry Seinfeld) only ever introduced him to Sharon (Paula Marshall) as "George."
When the reporter Sharon is interviewing Jerry and George in the apartment, she makes it a point to say "You should hear how my boyfriend talks to me." Yet, later in the episode she is making out with Jerry on his couch. Either she is cheating on her boyfriend, or she quickly broke up with him after meeting Jerry.