It’s Christopher Nolan's ability to construct an intensely puzzling experience that really makes this film stand out; it feels just as disorienting and irritating for the audience as it does for the central character, Leonard (Guy Pearce). The movie doesn't explain how he gained those intimidating ninja-like abilities, but we do see him attempting to uncover the truth behind his wife’s death while struggling with a severe lack of short-term memory. As he tries to make sense of things, he relies on leaving himself notes and photos covered in writing to keep track of his progress and determine who is trustworthy—or isn't. Important details are marked as tattoos on his body as his investigation continues – or at least that’s what it seems. He encounters various individuals about whom he possesses some records; with some, he has guidance for himself regarding trust, while with others, he doesn't. Some of the photographs show deceased people. We have a slightly better understanding of how those deaths occurred than he does, but it doesn't really provide anyone with enough information to figure out who murdered his wife. Could he have been responsible? It’s a truly convoluted film, full of unexpected turns and complexities—though they don’t feel unnecessary or irritating. The movie is the epitome of moving forward one step only to be pulled back two, and this confusion is heightened by Natalie (Carrie-Anne Moss) and an excellent Joe Pantoliano as Teddy, who becomes more prominent throughout his search. I also found the ending satisfying; it avoids easy answers and provides a suitable conclusion to what is a powerful film, showcasing Pearce at his best.

Source on TMDB