Continuity mistake: After Patience overhears the information about Beau-line and is chased into the warehouse: the guards come up behind her and see a well-lit full silhouette shadow of her, and she raises her left hand. However, when the camera point of view changes to show her face, her back is up against a stack of boxes/buckets, and there is no light source behind her.
Continuity mistake: At the very beginning of the movie Patience is at work. She gets yelled at by the boss, she goes home and can't sleep because the neighbors' music is too loud, then she goes back to work. It's the next day, but Patience, her coworker and her boss are all wearing the same clothes. They even make a point to comment on how awful her outfit is and she's wearing the same awful outfit the next day.
Revealing mistake: In the jewellery store when the robbers are smashing the display cases they shatter before being hit with the shotgun butts.
Factual error: Laurel shoots her husband dead and gets the fingerprints of Catwoman on the gun. When Catwoman/Patience later is interrogated for the murder, they say that her fingerprints were on the weapon that killed George Hedare. In a case like this, they would surely do a test for gunshot residue on both Patience and Laurel. The lack of GSR on Patience would at least have created certain doubts.
Continuity mistake: The police officer had to kick the apartment door down to get to Patience, but as she is hurrying out the door, the door jamb isn't broken and the door can latch normally.
Continuity mistake: At the carnival, when Tom and Patience are on the ferris wheel, there is an aerial shot of them starting to go down towards the ground. The next shot is one of them coming up over the top.
Continuity mistake: When Catwoman is on stage during the ballet, dozens of cops enter from every entrance/exit door with their guns drawn and flashlights on, as they walk down the aisles. As Catwoman runs out through the backstage, the audience applauds thinking it was part of the show and as they applaud the wide shot, from the balcony it shows the audience applauding but not one single cop is in the theatre, the aisles or on stage. No flashlight beams are even shown.