While some people think of the movie as being rather ambiguous, I believe there are enough pointers to solve most issues . For example, Leonard, our protagonist, is allegedly helped by Natalie, who seems like a good person. However, towards the end, she issues a tirade which makes it clear exactly what her real motives are. The final sequences are the most telling, where another person who Leonard isn't supposed to trust, Teddy , tells him what is really happening since he has been with Leonard since the beginning of his quest. Leonard's reaction to Teddy's "truth", and a failure to record it, illustrates the motivations behind his actions.
The movie's style of telling the story backward is interesting, but I'm beginning to discover that it's really not that hard to tell a story in this manner. Take a few your favourite books , reverse all the chapters/paragraphs, and with a bit of mental filler, you can easily follow the stories in most cases.
