Continuity mistake: Kramer's moussed up hair looks much different in the first shot compared to the rest of the scene; it's way slicker and frizzles up right after the first cut. (00:00:55)
Continuity mistake: When Morty's exercising first wakes Kramer up, his clock reads 5:30. Then in another shot, the clock reads 5:26. (00:10:05)
Continuity mistake: The exterior of the video store in the episode looks different from the interior. From the inside, we see a neon "open" sign on the window and other writing, and also no exit sign on the door, all of which is contrary to the outside view of the store. (00:09:25)
Continuity mistake: George teleports from being on the other side of the room to standing right next to Jerry after a cut. (00:02:45)
Continuity mistake: When Kramer is telling the fantasy camp story to Jerry and Elaine, the suitcase in the background is open different amounts during different shots. (00:09:55 - 00:10:40)
Continuity mistake: After Kramer walks into Jerry's apartment, he shuts the door. However, in another shot a couple seconds later, the door is inexplicably wide open. (00:01:45)
Continuity mistake: During a conversation with Kramer, Jerry is holding a drink in his left hand. Although he is never seen setting it down, the drink disappears in the next shot and he has his arms crossed. (00:02:10)
The Fix-Up - S3-E16
Character mistake: George calls Jerry to tell him about sex with Cynthia. He starts by saying he just got home, which Jerry repeats. A few lines later, George confirms they had sex at his own apartment. Why would he be getting home from his own apartment? (00:13:50)
Factual error: On the bottom of all checks, they have the routing number, followed by the account number, followed by a repeat of the check number found in the top right corner. When we see Jerry's bounced check, "1246" isn't seen after the account number.
Continuity mistake: When Jerry and Elaine are talking in The Apartment, after George and Kramer go see the horse, the G+W Motorwerkes magnet disappears from the fridge.
Visible crew/equipment: When George and Elaine are in the cab, you can see the studio lights reflected in George's and the cab driver's glasses.
The Stakeout - S1-E1
Continuity mistake: In the video store, we see Elaine put back Cocoon 2 and then doesn't pick up another video. But when she takes the video from Jerry, she's holding a video in her other hand.
The Stakeout - S1-E1
Continuity mistake: At the video store, when Jerry shows Elaine the adult video, he holds it with both hands with his right hand fingers under the box. In the next shot, he's holding it with only one hand, with his right hand holding it by the side.
Revealing mistake: After the scene in which Elaine tells Jerry about her confrontation with the "head-nodding" man, and before the scene where George swallows a fly, the scene cuts to a shot of the exterior of Monk's café. The actual, real-life restaurant used for exterior purposes is named "Tom's Restaurant," and the "m's" in "Tom's" can be seen during this five-second shot. (00:23:00)
Character mistake: When Jerry is being questioned on the lie detector test about "Melrose Place", the officer questioning him asks him two control questions that he responds to in full sentences. The questions should have been simple "yes" and "no" questions.
Continuity mistake: In the start of the scene when Kramer tells Elaine that the armoire got stolen. When Elaine walks in from the right side she walks right past the armoire, and it still has the two blue straps on it so it's the same one. The gaffe seems to have been edited out in some versions. (00:09:50)
Continuity mistake: While Jerry calls George from the coffee shop to tell him about the survey question, there is a shot of the waitresses and staff sitting at the tables. Behind them you can see the booths the gang usually sits at and there is a wall right next to the booth with pictures and pipes. Only problem is there are always booths next to the two near the front entrance. Even in this episode you can see the other booths as there are menus, condiments and napkins at the booths next to the regular booths.
Continuity mistake: When Loretta comes into The Apartment she is carrying a coat and roses in one hand and the other hand is supporting her handbag by her right shoulder (left on screen). In the next shot she is holding the bottom of the flowers with both hands instead of just the left hand.
The Airport - S4-E12
Factual error: In the episode where Jerry is upgraded to first class while Elaine struggles in coach, the scene changes to show a plane flying with the colors of Southwest Airlines, and you can make out the name "Southwest" written on the tail if you pause as it's landing. Anyone who has flown them knows that there is no first class on Southwest.
Plot hole: In the episode where Kramer decides to start sleeping like a Seal, he's with a girl. He falls asleep on top of her and she seems to think that he's dead. While breathing, your chest expands in such a way that if somebody were laying on top of you, there is no conceivable way that you could think that they are dead.
Answer: Composer Jonathan Wolff used a synthesizer, although in seasons 7-9, a real bass is used in addition. Wolff also recorded himself making hundreds of mouth noises, pops, and slaps to add to the synthesized bass licks so that each episode has a different theme. The only real "back-story" is Jerry Seinfeld was having trouble coming up with a theme song and talked to a friend who happened to know Wolff. They wanted to avoid that cheesy late 80's sit-com theme song and Wolff came up with what we enjoy now. Jonathan Wolff has also talked about this further in interviews, recently Reed Dunela interviewed him, so for a fuller account of his story; check out "The Wolff of 116th street".
Bishop73