* AdaptationFirst: It's based (very loosely) on the short story "Memento Mori" by the [[Creator/JonathanNolan director's brother]] but that story wasn't published until after the film opened. It's included on the DVD. The short story actually has a lot in common with ''Film/TheDarkKnight'', as many of Earl/Leonard's inner monologues are The Joker's verbatim.
--> ''So the question is not "to be or not to be," because you aren't. The question is whether you want to do something about it. Whether revenge matters to you. It does to most people. For a few weeks, they plot, they scheme, they take measures to get even.''\\
''You probably were the type to let it go, weren't you? Before. But you're not the man you used to be. Not even half.''\\
''Never-ending grief, never-ending anger. Useless without direction.''
* BreakthroughHit: It was [[Creator/ChristopherNolan Nolan's]] first big hit as a director.
* FromEntertainmentToEducation: The film has been used to better understand anterograde amnesia (that is, the inability to create new memories)
* ShrugOfGod: The DVD commentary splits into three parts in the last scene: one saying that [[spoiler: Teddy was lying to Leonard]], one saying [[spoiler: he is telling the truth]], and one [[spoiler: not saying either way]].