- Incorrectly regarded as goofs: Leonard is able to remember that he has a problem with his memory because he has conditioned himself to look at his "Remember Sammy Jankis" tattoo. Similarly he has conditioned himself to check his pockets for Polaroids to remind himself of other essential day-to-day facts. Alternatively, it could be because Leonard has Korsakov's syndrome, sometimes caused by acute trauma. In some cases the patient knows that they have the disorder. Arguments have been presented both for and against this but, in the end, it's the reality that the movie presents us with and so, for 113 minutes at least, it's true.
- Incorrectly regarded as goofs: ...or not - your call. Since the movie is about memory and its fragility/unreliability, it is eminently possible that all supposed continuity errors are deliberate. However, given the structural complexity of this movie, and bearing in mind the number of errors which manage to find their way into even the simplest linear narrative, it is equally possible that they are genuine errors and so they are reported here for your consideration.
- Continuity: Natalie's hair in the restaurant scene.
- Miscellaneous: When Natalie shows Leonard the picture of herself with Jimmy, she is smiling (in addition to Jimmy having a mustache). Later, when he gets out of bed and views it again, she is no longer smiling, and Jimmy's mustache is gone. Finally, in the close-up of Leonard writing the note on the back of the Polaroid he took of her, the picture has reverted to its original state.
- Continuity: In the opening scene, Teddy's glasses flip over between shots.
- Continuity: The size of the tape pulled off the roll and applied to Dodd's face.
- Continuity: As Leonard stands at Dodd's door preparing to enter, there isn't a window on his left side. Once Leonard breaks into Dodd's room, a window appears to his left.
- Revealing mistakes: The Jaguar XK8 has antilock brakes and would not have managed the entertainingly screeching skid as it stopped outside the tattoo parlor. Only the rear wheels are locked and clearly the handbrake was used to make an amusing noise. No matter how it was achieved, it was not a natural stop and there is no evidence to suggest that Leonard is a stunt driver who might habitually stop like that.
- Revealing mistakes: When Leonard discovers the bullets in the pickup, the primers are obviously used and would not fire.
- Continuity: When Natalie kisses Leonard goodbye, her lips are not cut, though they are before and after.
- Audio/visual unsynchronized: In a couple places, such as after Jimmy is killed, the Polaroid camera does not make the correct motor noise.
- Continuity: When Leonard burns Catherine's hairbrush in the fire. you can see that Catherine's book is also burning next to it before Leonard has put it into the fire.
- Continuity: At the beginning, when Leonard and Teddy arrive at the abandoned building the weather is cloudy, but when they get out of the Jaguar it becomes sunny all of a sudden.
- Continuity: When Leonard is writing on the back of Teddy's Polaroid, he sets the picture down on his jacket; however, in the close-ups of Leonard writing, he appears to have the picture directly on the bed.
- Continuity: When Leonard is being chased by Dodd, Leonard's window is intact, broken, and intact in successive scenes (before it is shot out by Dodd shortly thereafter).
- Crew or equipment visible: When Dodd pulls his red vehicle into view after Leonard turns off the road to see what he was harassing him about, the camera crew is reflected on the side as the truck moves from the right side of the frame to the left.
- Crew or equipment visible: When Dodd blocks Leonard in with his SUV the entire camera crew and camera is reflected in the rear of his vehicle.
- Continuity: In the scene where Burt admits to renting Leonard two rooms, Leonard refers to him as Burt. Burt never told him his name.
- Miscellaneous: When the tattoo labeled Fact 6 is being made at the tattoo shop it clearly shows SG1371U while Leonard is saying SG137IU.
- Miscellaneous: When Lenny is sitting in his pick-up writing down teddy's licence number, he writes "FACT 6". How does he know what fact number it is? He didn't look at his tattoos to check how many other facts there had been. He wouldn't have been able to remember.
- Revealing mistakes: Look at the handwriting on the Ferdy's Bar coaster. In alternating scenes the writing is in print and in cursive.
- Factual errors: Although Lennie's problem was identified as a loss of short-term memory, his short-term memory was fine because he could remember what had just happened. His problem was that he couldn't transfer his short-term memories into long-term memories.
- Continuity: Teddy's car's license plate changes throughout the movie. The first time we're able to see it (after Leonard and he leave Dodd's apartment), it reads SG13 71U. Towards the end, after Leonard kills Jimmy, it reads SG13 7IU, which is what Leonard reads it as every time he mentions it. Tattooed on his thigh, it reads SG13 71U, and on the vehicle title Natalie provides for him, it reads SG13 7IU. This, of course, is likely an intentional mistake to reflect Leonard's unstable state of mind.
>>> WARNING: Here Be Spoilers <<<
Goofs below here contain information that may give away important plot points. You may not want to read any further if you've not already seen this title.
- Continuity: SPOILER: At the end of the movie as he is driving the Jag, he closes his eyes and sees himself with his wife. His shirt is open and the tattoo's are visible, including one that that says 'I've done it'. But as with the Fact 6 License plate error, he doesn't remember he has tattoos until he sees them. However, his thoughts are in the same memory timeline in which he kills Jimmy G. and changes clothes. He could have seen the tattoo for fact 5 then, but not the tattoo written backwards along his collar bone.
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