Continuity mistake: When Gatsby points out to Tom that his house is across the bay, there is then a shot of the house from Tom's view. The shot returns to Tom where we can see nothing around the top few inches his abdominal area. In a side angle of him, his cigar has suddenly appeared there. (01:28:35)
Continuity mistake: When Tom stops at George's gas station, he looks at Myrtle from her window. In a shot of Tom, Jordan is seen in the background looking in the same direction as Tom and places her hand on her glasses. In a close-up, she is looking straight forward and her hand is no longer on her glasses. (01:33:05)
Continuity mistake: When George kills Gatsby, Gatsby falls into the pool with his arms by his side, but from a reverse angle, his arms are raised in the air. (02:02:35)
Continuity mistake: While Gatsby drives with Nick he takes his hat off and waves it, then it's back on, and then back to the previous angle of him waving it.
Continuity mistake: At the Plaza Hotel, Gatsby loses his temper and a strand of hair falls on his forehead. He takes both hands to button his jacket and when the angle changes his hair is brushed. His hands were too busy for him to do it between shots.
Continuity mistake: Meyer meets Nick and places his hand on his shoulder. A frame later Meyer is standing sideways, several meters away from Nick.
Continuity mistake: When Nick meets Gatsby at the party, the amount of confetti on his shoulder and hair changes between frames, sometimes appearing or disappearing on the same spot, depending on which angle is shown.
Continuity mistake: When the doctor tells Nick to write the story, the pen's position differs between the close-up and wide angles from being in a 5 o'clock or 12 o'clock position.
Continuity mistake: During the meal where Gatsby is about to say that he and Daisy are in love (before the trip to NY), Daisy's fringe is messed up in the wide angles, but perfectly brushed in the close ups. This changes back and forth.
Continuity mistake: Right before Myrtle is run over, she runs down the stairs, hair messed up. She stops for a brief second where the angle changes to a close-up, when her hair style changes completely.
Continuity mistake: After Gatsby tells the story of how he met the sailor there's a blue shirt on the bed which disappears when he exits the library.
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: 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: When Tom discovers that he is going to be abandoned by Daisy, he extinguishes his cigar. The grip swaps from holding the tip to being on the middle part of the cigar, between shots.
Continuity mistake: When Nick meets Jordan, she is sitting on the sofa holding a magazine with both hands, yet less than a second later she manages to be lying horizontally.
Continuity mistake: When Gatsby finishes throwing the shirts at Daisy, the type and amount lying on the floor changes between shots.
Continuity mistake: While Gatsby says the "you can repeat the past" speech, Nick is standing against a column. Then the shot changes to a wide angle where he starts to walk away. Then, suddenly, the previous angle is used and Nick is back next to the column for the rest of the scene.
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.
Continuity mistake: Early in the film Tom brings Nick to meet with his mistress Myrtle - and set Nick up for some drinking and debauchery. While waiting for Tom to come out of the bedroom Nick is sitting in a small parlor with Myrtle's dog. In the first wide shot we see the dog licking an empty plate. Cut to an expression shot of Nick staring awkwardly, then a close-up of the dog - but now a small pile of dog food has appeared on the right side of the plate. Another reaction shot of Nick, then back to the dog - but the food has moved to the left side of his plate.
Chosen answer: The song is "Back to Black" by Beyoncé (Feat. Andre 3000).