Okay, all of you are completely wrong.

Great movie. But I do have to say this reading the thread: while many people love to interpret a movie they’re own way, and I’m bound to come up with my own theory, we should really only be dealing with facts here, especially on The Straight Dope. Granted, its MPSIMS, but gross generalizations and conjectures are misleading, and should be prefaced with an admission of a WAG.
Like many in here, I think one of the key elements in this movie is the scene where we see the tattoo that reads “I’ve done it”, which can be seen here:
http://www.ece.mcgill.ca/~mperez1/memento.jpg
What is extremely important is the fact that right above this tattoo is the backwards tattoo that we’ve all seen in the movie that reads, “John G. raped and murdered my wife”.
Murdered? Then who the hell is that laying naked next to you?!?
Also, for those of you who’ve seen it a couple of times, what are the exact words and motions that Natalie makes when mentioning the spot where the “I’ve done it” tattoo “appears”?
Thirdly, what’s the deal with the picture of Lenny pointing at his chest? Everything is so blurry to me, that I don’t remember any of the conversation that took place regarding this. It appeared during the B&W scene in the hotel while Lenny is giving the Sammy talk on the phone (which I assume to be before he kills Jimmy, correct?), and after he kills Jimmy, when he burns that picture, and the picture he took of the dead Jimmy. Obviously, there is no “I’ve done it” tattoo on him in the picture, but is there a scar?
Enough with the questions. On with the comments. My browser is being picky, so I can’t quote anybody. With that said, someone mentions something about Lenny having the tattoo the whole time, but refuses to see it. I think this is bunk. The movie would have given us more clues if this was the case (like showing him with the tattoo, but him looking in the mirror at himself without the tattoo). I don’t buy it.
Damn, I need some answers! (Actually, I just need to go see it again…)
Thanks in advance!
Munch