Continuity mistake: When Decker shoots the snake-woman replicant, she hits the glass and in one shot you can clearly see that is not the actress that hits the glass, but a stuntperson dressed like her. This has been corrected in the 2007 Final Cut of the film, but exists in all previous versions.
Continuity mistake: When Deckard shoots the snake-woman in the back and she falls through several layers of glass she lands on her stomach, with her head lying on the left side. In the next scene Deckard is standing beside her, but now she has turned her head, lying on the other cheek. Her arms also change position.
Continuity mistake: After Pris and J.F. Sebastian startle each other, they begin to talk for a moment. Watch J.F.'s hands as he says "Don't worry, I won't hurt ya." In the side angle, his left hand is hidden and his right hand is fidgeting with the bag he is holding at his chest. It then cuts to a view from over Pris' shoulder and suddenly his right hand is now hidden from view and it's his left hand fidgeting.
Continuity mistake: After Leon puts his hand in the freezing liquid holding the eyes, warranting several angered scolds from Chew, Chew looks at Roy in puzzlement. Between this shot and the shot after Roy says "Yes... Questions." The head gear on Chew's head moves up on his hat. The position of it changes several times during this scene.
Continuity mistake: After Gaf takes Deckard to his police car to go see Captain Bryant, he looks at a screen that is blue, then turns red and says PURGE. He looks down and to his right when he sees this. Moments later as they are flying in the vehicle, a view from the back seat shows the front dash with two screens. The one in the center, which would have been the one he was looking at since he was looking down to the right, is now much skinnier than it was moments before. It's the one showing green and orange text now.
Continuity mistake: After he finds dead Pris, the blood smears on Roy Batty's lips change. He touches her bloody wound with the fingertips of his right hand and then presses them to his upper lip. You will see two parallel smears of blood. Moments later there is only one smear going from his upper lip all the way to his chin.
Continuity mistake: The Asian chef calls Deckard over to order his food once a seat becomes available. There is a guy in a yellow shirt sitting next to the open seat. A blue bottle of some sorts is right next to this guy's arm. When Deckard comes over, the blue bottle has vanished. It appears again once Deckard sits down to his left by the yellow guy's arm. And then after the chef gives Deckard his food, the blue bottle is suddenly on Deckard's right.
Continuity mistake: While waiting in the rain for his food, the chef across the street calls Deckard to come over. Deckard folds his newspaper and puts it over his head to shield himself from the rain. The paper is folded messily and the crease side is in his hand. When he gets to the other side of the street, the fold is suddenly much cleaner and neat, and the crease side is on the outside, no longer in his hand.
Continuity mistake: The scene where Roy saves Deckard's life and then dies takes place on a very dark and rainy night. After Roy says his final line, "time to die", the white dove in his hand gets loose and flies away. The next shot shows the bird flying in a totally clear cloudless sky, with lighting that suggests that it is becoming morning. The next shot is of Deckard, back in the heavy rain and total darkness.
Continuity mistake: When Deckard is snooping about in Zhora's dressing room asking questions. We see her putting on high heel mid-calf boots (just under her shin pads). Watch the chase sequence soon after. Especially when she gets shot and is on the ground picking herself up, you can see she is wearing what looks like black trainers.
Continuity mistake: When we first see Deckard he is sitting down and reading a newspaper. After a little bit of time a seat becomes available at the restaurant across the way. The cook calls him over. Deckard then folds the newspaper once and places it over his head to shield himself from the rain. We see him run across the thoroughfare and off camera. It then cuts to him making his last couple steps to the waiting seat and the newspaper is now folded twice.