In the scene when Mimi cuts her hair for the first time and bakes a Turkey for Oscar, he is wearing the same turtle necked blue sweater that was ripped off with a razor blade during a previous sex game.
At about 1:49 when Mimi takes off her shoes and Oscar has wet himself, the position of the visible shoe on the floor varies between shots (points 180 degrees the other way).
At New Year party confetti is in Mimi's hair and face, but in the very next shot of her where she wishes a happy New Year to Oscar, there is no confetti on her.