Continuity mistake: When Joe awakens after his first night at Norma's mansion, his shirt is un-tucked as he puts on his jacket to go outside. When he is running down the stairs in the next shot, his shirt is tucked in. (00:26:35)
Continuity mistake: Gillis is lying on his bed with the script pages all over the bed. Look closely and you'll see that they're all copies of the same page.
Continuity mistake: Gillis steps out of the pool, dries himself and then Norma Desmond helps him dry again. When the shot changes, his face is totally wet again.
Continuity mistake: When Gillis is seen floating in the pool, a photographer on the left kneels down twice to take the picture: First in the wide shot, and a second later in the closer shot.
Continuity mistake: Desmond throws a bunch of papers tied up with a string at Gillis. Shot changes to him catching them and the bundle is totally different.
Continuity mistake: When Gillis enters Schwab's pharmacy, the wide shot for the exterior shows a man and a woman on the left of the entrance. In inside shots they are gone. When Gillis steps outside, the prior exterior shot is used and the man and woman appear again.
Continuity mistake: When Norma tells Gillis that "movies got smaller", the angle has changed from a wide to a close-up. After her line it cuts back to the wide angle. The position of her head doesn't match between these two.
Continuity mistake: In the opening scene, the second police car starts off as a 1941 Plymouth, except it's a Ford during the cut when they are pulling into the driveway (same as the first police car). It switches back to a Plymouth when they pull in front of the house.
Continuity mistake: Gillis enters Norma's bedroom and she is crying, saying she's got a gun. In the close-up she raises her head but a frame later, from a different angle, it's resting on the pillow.
Continuity mistake: At the end of the movie as Norma descends the long curved staircase, she is being tracked and lit from below by a man holding a fixture with four flood lights. She is on the stairs - he is not. But when Norma stops at the bottom of the staircase for her close-up, the man with the lights is now suddenly on the staircase with Norma standing behind her.
