Let Me In turned out to be just plain creepy and wrong in my opinion. Moretz plays a young girl that appears to only 12 or so, but in reality is significantly older. She craves blood and survives by meeting young boys, making them fall in love with her and then take care of her for the rest of their lives.
They kill her victims, so she doesn't have to. When she moves to an apartment complex, she meets a boy and immediately begins attach herself to him. What is disturbing in this movie is the sexual overtones between Moretz and her now adult guardian as well as the young boy. Both are willing to do anything for this little girl, but the adult jealous when she attempts to move on to her next child guardian.
The movie definitely has a unique take on the vampire mythos and perhaps the sexuality is disturbing to me because I am a parent. I was very uncomfortable watching the scenes of sex and sensuality. If you are able to look past that aspect, the movie is good, but violent. This definitely earned the R rating for many reasons. Moretz does a good job of portraying a child that is far older than she lets on, but some scenes can be disturbing to watch.