Continuity: Adrian's chalk sketch of Dorian Gray on the table changes from shot to shot.
Audio/visual unsynchronized: When Sibyl Vane first catches sight of Dorian while she's performing "Goodbye, Little Yellow Bird," she momentarily stops singing, but her voice can still be heard on the soundtrack.
Revealing mistakes: When Dorian is riding the train early on, the scenery of the rear projection outside the train window changes from passing trees to open fields.
Revealing mistakes: When Lord Henry first spots the butterfly on the drape in Basil's studio, the mesh edges of his fake beard are clearly visible.
Continuity: At 34:35 into the film, the time on the clock in the room suddenly changes from just after 2 o'clock to 3 o'clock. At 37:00 it moves back to 2:05 and then to 2:09 as Dorian continues to pay the piano.
Continuity: When Dorian confronts Allen Campbell with the blackmail letter in his drawing room, Allen sits at the round table, which has only the cat statue and the letter on it. In the next shot there is a writing implement on the table as well.