Continuity mistake: In the scene where Mariah, is on the "not a date" with Dice, and they're having dinner, they start to talk and in the different shots you see that the amount of wine in the glasses changes in every shot.
Revealing mistake: The films takes place in and around NYC. The nitpick here is that in many scenes in the film Torontos CN Tower and The Sky Dome are visible in the background.
Factual error: In 1983, Billie covers "I Didn't Mean To Turn You On" which was not released until 1984.
Continuity mistake: When Billie kisses the music sheet, she is wearing pink lipstick, but the lip print is red.
Continuity mistake: When Billie enters the apartment, she finds the song Dice wrote for her. Between shots before she picks up the sheet, the amount written on it changes.
Continuity mistake: After Billie kisses the music sheet, the pencil in front of it is laying so that you can see the brand name on the side of it. When Dice goes back later, the pencil is all yellow, and the writing isn't visible on it anymore.
Continuity mistake: When Billie, Roxie and Louise dance under the silver glitter, Roxie has two pieces of glitter stuck under her neck, which both fall off. In the next shot one piece is back.
Continuity mistake: When Billie sings "I Didn't Mean to Turn You On" on stage for the first time, the microphone cord wrapped around her hand and arm, and her hands on the microphone pole change position in every shot.
Plot hole: When Billie and Dice are in the limo, Dice mimics what Rafael said to Billie at the party. However at that point Dice was not with them to hear this - he was off in the crowds at the party.
Continuity mistake: When Billie is sitting at the keyboard, and she puts a pad down, and lays a pen on top. Between shots the pen rotates - note the direction which the pen nib faces.
Continuity mistake: When Dice is discussing with Billie his future as her producer, he has a drink in his hand. During the conversation, he takes a sip, and lays it down in a position on his chest where, if there truly was liquid in the cup, it would have spilled out; then proceeds to keep drinking as if there still was liquid in the cup.
Revealing mistake: Shots of the public walking on the street reveals people using modern cell phones, not from 1983.