Continuity mistake: While Gatsby and Nick talk when the party is over, during the "repeat the past" scene, Nick walks down the steps and a piece of fabric behind him swaps from bright red to dark brown randomly.
Continuity mistake: In the scene where Meyer is having a conversation with Nick in the bar, the dancers on the stage begin to walk off and walk around the bar. One of them walks behind Meyer and places her hands on his shoulder, but in the next shot, the dancer's hands are no longer on his shoulder. (00:42:50)
Continuity mistake: When Tom and Nick get off the train and go to Wilson's shop, in a close up of Tom's face you see him look up toward the window (looking for Myrtle). After that it cuts to a wide shot and you can see Tom in the background repeating what he did in the close up.
Continuity mistake: During the first party scene, when Nick is ascending the stairs having a conversation with an unknown Gatsby, it cuts to a wide shot where Gatsby is standing at the top beginning to turn and give his "I'm Gatsby" line, it then cuts back to Nick and Gatsby continuing their ascent of the stairs. When they reach the top Gatsby is now in the position shown from the wide shot. (00:29:20 - 00:30:15)
Continuity mistake: When a band starts playing at Gatsby's party, Gatsby and Tom look and smile to each other. In the next shot, Tom is suddenly not smiling and looking straight forward at the band. (01:12:35)
Continuity mistake: After Gatsby shows Daisy his scrapbook of her, his phone rings. He walks over to it, picks it up and answers it. He has the phone in his right hand and the rest of the phone in his left. In the front shot, his left arm is bent whilst he holds it, but in the reverse angle, his arm is now rested. (01:05:30)
Continuity mistake: When Gatsby, Nick and Daisy have tea together, a shot of all three shows Nick and Daisy to the left of Gatsby. Camera switches angles and Gatsby is now in a different position than the previous shot. (00:56:50)
Continuity mistake: As Nick narrates "The way he spoke" during the driving scene, he is looking forward in one shot, but looking slightly to the right in the next. (00:36:35)
Continuity mistake: When Gatsby says "I was bought up in America" when he is driving with Nick, he is looking straight forward. In an instant close-up of Gatsby, he is suddenly looking at Nick. (00:36:30)
Continuity mistake: When Gatsby and Nick are driving in the car, Gatsby asks Nick "What is your opinion of me anyhow?" After he finishes this line, his mouth is open. But in the next shot, his mouth is suddenly closed with no time to do so. (00:36:05)
Continuity mistake: As Jordan walks to Gatsby's room at his party, she begins to walk and has already walked past a waiter who goes to take a step forward. But in the following wide angle, Jordan is yet to walk past the waiter who is now standing still. (00:31:55)
Revealing mistake: The doctor tells Nick to write his story and Nick says he isn't any good. The next shot shows a blue screen reflected in the doctor's glasses. (00:14:00)
Continuity mistake: After Nick finishes telling the part of the story in which he saw Gatsby on the dock, he has a finger placed on the glass. In the extreme close-up, the other three fingers to the right of him are raised to the same level of the finger on the glass, just a little bit lower. Yet in the next shot, the other three fingers are suddenly lowered notably. (00:13:30)
Continuity mistake: When Jordan goes to listen on Tom and Daisy's conversation after Tom goes to the phone, Nick asks "Something happening?" This shot shows his head half turned to Jordan. In the next shot, his head is even more turned than before. (00:10:15)
Continuity mistake: When Nick says to Daisy she is missed in Chicago, she says "How gorgeous." The shot cuts back to Nick. In this shot, his tie perfectly straight, camera cuts and his tie is slanted a little. (00:07:35)
Continuity mistake: When Nick is telling the doctor about his new cottage near the start, he goes to his porch with a book and stands next to one of the pillars. In a wide angle, he is standing next to a pillar with leaves around the pillar, but in a sudden close-up the leaves around the pillar have vanished. (00:04:40)
Revealing mistake: When Nick starts talking about Gatsby to his doctor, a green reflection is visible in the doctor's glasses when the doctor says "Where'd you meet him?" There's no other object in the room that is that style of green (it's most likely a green screen). (00:03:00)
Continuity mistake: In the beginning scene, Nick has a conversation with his doctor in the Perkins Sanitarium. The shot after Nick says "When I came back from New York I was disgusted" shows the doctor open his file. When he opens up the file, Nick's name is placed next to patient name and below it is "Patient Report (by board of examiners)." In this shot the "N" is directly above the "Y" in "by." But in a quick close-up of the file,"N" is now directly above the "O" in "board." (00:02:00)
Continuity mistake: When the doctor says "He was your neighbour", Nick's head looks out the window in a 180 degree direction. In the next shot, his head is suddenly turned 90 degrees to the right. (00:05:20)
Continuity mistake: While driving the yellow car, Gatsby flashes his business card at the cop, whose head swaps between looking sideways or straight ahead depending on the angle, no continuity whatsoever.
Chosen answer: The song is "Back to Black" by Beyoncé (Feat. Andre 3000).