In the first scene in Sidney's office, the secretary picks up a stack of magazines and newspapers that changes position and height from shot to shot.
The look of Susan's hair changes noticeably during closeup scenes between her and J.J. as she is preparing to leave the apartment near the end. There is a closeup of Susan near the door, then of J.J., then back to Susan. In that last closeup of her, both the volume and how her hair lies has changed noticeably.
When Sidney is trying to see the column in advance, the position of the secretary changes. This is when she moves the copy from one side of the desk to the other.
During the theater confrontation scene, Hunsecker is writing on a small note pad, but the pad and pen suddenly vanish from his hands as he and Falco move up onto the stage.
(at around 37 mins) Sidney Falco (Tony Curtis) is clasping his hands together and rubbing them while he speaks to Otis Elwell (David White). The shot cuts to a front view where Curtis's hands are down by his sides. There are several other small continuity issues throughout the movie with the placing of hands.
When Susie departs from JJ at the end, she exits from the Brill building. The Brill Building never had private residences, nor did it have balconies.
(at around 2 mins) When Sidney peruses J.J. Hunsecker's 'The Eyes of Broadway' column on page 21 of the New York Globe newspaper, it can be seen that several of the paragraphs are repeated. Of the nine paragraphs visible, it can be seen that paragraph 7 is an exact copy of paragraph 2; 8 is a copy of 5, and 9 is a copy of 4.
Moving shadow of the boom microphone is visible in the upper right of the frame when J.J. is phoning Lt. Kello to tell him about the "plant".
Microphone shadow during coffee shop scene with Steve and Susan.