I asked my dad if I could see the movie and says that it's too violent. From what I've seen in the parental guide I don't understand it. Either my dad thinks it's too violent or what it says in the parental guide is more violent and disturbing than what you read.
This ain't a big action movie, though it has a little violence. There are two fight scenes and two kills. Also it contains footage of someone using drugs and contains dirty language.
Where I live the ratings are different then the US. Here it's not named by R, X, Pg and that kind, but only with a number which is the minimum age. There is ALL, 6, 12, 16 and 18.
6 are movies like Harry Potter, 12 are some action/thrillers/dramas, 16 are basically all movies except those with nudity/porn, those are 18.
Even though theaters are forced by law to check ages, it barely happens here. (note: a child of 3 won't be allowed at an '16', but if your 12 you could probably get in easy!)
This law doesn't apply at home. When I am watching a DVD, I can let small children watch too. Though everyone recomends to stick with the rating.
To be honest, if I should rate Memento, I would rate it 12. There is a little of this and a little of that in the movie, but not much. Though, I think you should listen to your dad. I come from a rough country, we are used to much more in TV and Movies!