Goofs

Karl Lundgren shot Joe Brody four times, then two shots at Philip Marlowe just outside of Joe Brody's flat and then continued to shoot whilst running away. That's too many shots for a standard six shot revolver.

General Sternwood says both his legs are paralyzed yet at different times his legs can be seen moving under the blanket draped over them.

When Marlowe brings Camilla home from Geiger's house, the shot from the car to the Sternwood's door shows Marlowe's car door open. The reverse shot from the house out to the car shows his car door shut.

Marlowe retrieved a 6-shot revolved from his car. When he attracted the attention of Lash Canino, he fired 2 shots into the window, but when he emerged from the burning car's smoke, he fired 6 more. Too many.

When Marlowe takes the gun from Camilla after she unloads it on him with multiple blank rounds, he grabs the barrel with his bare hands. That should have proved to be very painful as the barrel would be extremely hot.

EDIT: This is incorrect. Blank cartridges in a small calibre gun will not heat the barrel to any great extent. A gun barrel gets hot mainly due to the friction of the bullet going through the barrel, not from the powder in the cartridge.

On the night of Geiger's murder, Marlowe returns to Geiger's home in a Taxi (20:18) with a number plate 7077. Next day, Marlowe follows a truck from Geiger's shop (25:26) in a taxi with the same plate 7077 after stopping the taxi in the street.

The dangers of firing blank cartridges. Camilla repeatedly fired the auto pistol loaded with blank cartridges at Marlowe as he casually walked and came within close distance. Within 4-6 feet or so of the muzzle the blast effect of the super-heated high pressure gas as well as partially burned particles of powder can cause significant injury, even mortal wounds.

When Marlowe set up Camilla at the end of the movie, and she turns to fire the automatic at Marlowe, the pistol cycles for all the shots. Blank cartridges do not have enough energy to cycle an auto pistol designed for regular ammunition.