What makes this film great? (not a trolling post, not what you think)

Who knew Christopher Nolan before this film? Brilliant to tell the story backwards because the guy can't remember sh*t. It's pretty much that simple.

Soundtrack is haunting, adds to the flavor of the film.

"You can just stand there, ... and let him kick your ass!"
--Sensei Terry Silver Karate Kid III

That's a very good question, and makes me suspect you are involved in filmmaking yourself. I have only come across a handful of people on imdb with the vision to ask about manipulating a film's variables.

In my opinion, there are a few main factors in why others rate this film as great. I only think 1) and 3) are valid though.

1) Novel narrative structure. Most importantly, this film pushed the envelope in non-chronological storytelling. And it's why so film theory books reference Memento when tackling this subject. I challenge you to find a movie that's as creative as this in non-chronological storytelling.

2) Complexity. Nolan is known for his complex, cerebral plots, and I know that many people find it hard to keep up. This I feel has become a kind of test by which movie-goers prove to themselves they are clever enough.

3) Underdog filmmaker. This was his first properly-budgeted attempt at a feature-length film, and he showed everyone how innovative stories can break through the fierce competition of Hollywood. Similar to Reservoir Dogs. Both Nolan and Tarantino leveraged their creative limitations.

To answer your other question, yes, I think you could use this template of memory-inhibited-detective to backwards-tell a story with a different mystery and a different theme (why not?), but anyone who does so would be rightly jumped on for plagiarizing a novel idea.

I think there are big flaws in this film, but it's certainly an inspiring piece of work to aspiring storytellers.

Three stories come to mind about amnesia:
1. The October Man
2. The Scarf
3. Alfred Hitchcock's 'Premonition'.
You'll be surprised how Memento builds on all of these previous works.

Best unknown feature at IMDB.com
http://www.imdb.com/features/video/browse/

The movie is told in such a way that keeping up with what's going on is something of a mental exercise, and (to me, at least) it's engaging enough to motivate one to do so. Watching it is intellectually stimulating, and that's definitely a good thing.

It's far from the only movie to do so, but I think it's the one that does it best. Primer (2004) is even more complex in its storytelling, but that works to its disadvantage (it gets just a little too difficult to keep up, which is somewhat discouraging). Coherence (2013) is a bit too easy to follow, so it isn't as satisfying to actually manage to do so. Memento (2000) strikes just the right balance (of course, just because it's the right balance to me doesn't mean it is to everyone).

Don't listen to the negative ones; their arguments are irrational.

...people who have anterograde amnesia...

I would be interested in seeing the edit where the story is told in chronological order, but only because I've seen it the original way and love the film so much.

I don't think the story would be as effective, however.

It's reverse order motif is effective for putting the audience in the same dilemma as the main character, Lenny.

I think that you raise an interesting question, and I'm going to start with a disclaimer - this is my favorite film, so it's hard for me to see the wrong.

I've watched the chronological edit, and still found it an interesting story, though, admittedly, my mind was piecing things together as I had originally seen it. I do think that the chronological version doesn't stand up to the final edit. I think that seeing the story through an amnesiac's eyes is what makes it special.

Someone in another comment brought up Irreversible, which is another film that I appreciate, but not on the same level as Memento. That may be for other reasons, and parts of the edit of that movie make me physically ill, but I appreciate it all the same. It may be personal preference that draws me to this type of storytelling, as I also appreciate stories with unreliable narrators in general.

With that thought, I think that unreliable narrators is probably the most general genre in which Memento belongs. The most recent film of that type that I can think of is Gone Girl, which I also liked.

So, long winded comment short, I think that Memento is special. However, I don't think that it is so special that no other film can compare to it. It does have a good mix of everything that makes it rise above the rest.