I just watched Memento yesterday. It's one of the best movies I've ever seen. But I was confused at the end. Did Lenny killed "real" Mr.G or didn't? And was his "condition" real or was he just playing it? (Remember Sammy Jankins and that)

Awesome flick.

Sammy is Lenny. He manifested Sammy as a placeholder for himself. Thus, Sammy's wife, in turn, is really Lenny's. She survived the attack, but Lenny doesn't remember.

And he does kill Mr. G. He's the one who's body is in the basement.