BEWARE OF SPOILERS
- Memento's backwards narrative can feel somewhat gimmicky, but it forces us to live through Leonard's perception of the world, seeing a scene with no knowledge of the (usually critical) events that lead up to it.
- One thing that lends credence to the theory that Teddy is telling the truth about Leonard's wife surviving the attack and it was Leonard who killed her is that even in the heat of their argument at the end, Teddy always specifically says that the assailant raped Leonard's wife, never including that he killed her.
- Leonard's story about Sammy Jankis is not only revealing about how Leonard is able to form new memories, it's also possibly Leonard's only real memory of how his wife actually died.
- Most of Leonard's tattoos are written in a way that you can read them normally. The tattoo about the man who killed his wife is mirrored. When Natalie points out that the tattoo is backwards, Leonard says "It's... it must be for when I've found him." Leonard doesn't know it, but if he ever finds the killer, he'll be looking at a mirror.
- Teddy repeatedly asks Lenny for his car keys or tries to bluff Lenny into letting him drive his car throughout the film, without success. This is because Lenny has recently murdered the expensive and conspicuous Jaguar's owner, and Teddy is trying to dispose of it discreetly, as well as get his hands on the $200,000 inside.
- When Sammy Jankis is gets the electric shocks in the flashbacks, he barks out, "What the fuck?!" and "Test this, you fucking quack!" while giving the doctor the finger. It seems out of place for a mild-mannered accountant to use language like that... until you realize that, most likely, Leonard himself was the one receiving the shocks, and Leonard is quite the potty mouth.
- Come to think of it, if Leonard's memories of the assault are anything to go by, it's really unlikely that it could have been done by a single attacker: Lenny shot the first one in the head, almost point-blank, probably killing or incapacitating him instantly, and he himself, judging by his severe memory loss, probably passed out within seconds after having crashed into the mirror. So how could they have inflicted it on each other then? Looks like the police investigation WAS shoddy after all.
- At the end of the movie, you can be left with two conclusions: that Teddy was lying to Leonard, or that he was telling the truth. Which means that either Teddy is a Manipulative Bastard, or that Leonard is taking advantage of himself just as much as the rest of the cast. Neither interpretation is especially happy, but which one is worse?
- Teddy reveals that the man who raped Leonard's wife is already dead, and was just a random nobody. So why did Leonard pick the alias "John G." for this guy he was supposedly still pursuing? He was already planning on killing Teddy (real name John Edward Gamell) at some point in the future long before the events of the movie took place.