Excellent post. Some dim-witted reviewers of the film said that if a story isn't interesting moving forwards, then telling it backwards is just a gimmick. Your post certainly dispels that notion. These reviewers don't realize the full implication of what they're saying. If that were true, then most detective stories wouldn't work, because they move largely backwards, in effect. The investigation moves forward, but the revelation of the crime moves backwards (usually): from the dead body, the detective finds who was seen with the victim last, who spoke with him last, what happened just before the death which may have provoked such violence, etc., etc. The manipulation of story information -- when and how it's given to the audience -- is a key element of storytelling. Memento uses this brilliantly.

Right on, Ted! A great observation about detective stories which do, in effect, work backwards to the original crime. In fact, I've read more than a few interviews with mystery writers who do their plotting backward, starting at the resolution of the story, then working their way back sequentially in an attempt to create as many diversions and twists along the way. "Manipulation of story information." Reminds me of that quote from screenwriter Jon Spaihts (Prometheus): “So much of screenwriting is information management. A script is made of interlocking chains of necessary revelations.”