This is not about the movie by the same name starring Elisha Cuthbert and Emile Hirsch. It has the same name, but it sounds more like Martyrs to me.
https://en.wikipedia.org/wiki/The_Girl_Next_Door_(2007_film)

I just casually started watching this, last night. I didn't really understand what it would be about, it just caught my eye when I was scrolling thru the free movies.

I only watched about fifteen minutes. You have to be in the mood for a movie like this, I guess. Or at least, you have to be prepared. I was just starting to get into it, thinking "OK, this seems a little like Stand By Me or maybe It. I can get into that." But I started to notice little signs that it could get much darker.... luckily I paused it, and checked out its Wikipedia page, and read a few reviews on our old pal IMDB.

YIKES. Not for me. Apparently it's even based on a true story. I'm glad I turned it off. They take time to make you like and respect a couple of the characters, but then later in the film they just torture the bejesus out of those characters. Apparently Jack Ketchum had some kind of input into writing up the story, so it would definitely have to be pretty brutal.

So. Yah. It's possible I'll be in the mood for this at some point, but I'm glad I turned it off. If you look at Stephen King's comments on it in the Wikipedia article, you'll see that he said this: "The first authentically shocking American film I've seen since Henry: Portrait of a Serial Killer over 20 years ago. If you are easily disturbed, you should not watch this movie. If, on the other hand, you are prepared for a long look into hell, suburban style, The Girl Next Door will not disappoint. This is the dark-side-of-the-moon version of Stand by Me."

Once again: Yikes.