If you've already read Gillian Flynn's blockbuster novel, you already know the secrets of "Gone Girl." Outsiders might think that means you'll see each twist coming when the movie hits theaters on Friday (October 3), but what they don't know is that there's so much more to the disappearance of Amy Dunne.

Twists and hidden meaning aside, David Fincher's long-awaited adaptation of "Gone Girl," written by Flynn herself, finally hits theaters - and there's good news for fans and newbies alike. The movie delivers the same brutal story as the book, and will chill audiences in the same way that made readers look suspiciously toward their significant other.

Whether you've memorized the book front to back, or don't know the first thing about it, here's everything you need to know (spoiler free!) about the "Gone Girl" movie.

1. It's perfectly cast.

"Tyler Perry?" said the entire book-reading world when Madea landed the role of Tanner Bolt, but he's absolutely essential to the spirit of the film.

As are Neil Patrick Harris, Kim Dickens and Patrick Fugit. Top to bottom, the cast fits perfectly into this twisted world, but special praise is due to Carrie Coon, making her feature film debut. As Nick's sister Margo, Coon adds a level of humanity to the movie that saves it from become overly cold.

2. You'll like Ben Affleck even when you hate Ben Affleck.

Oh, you don't like Ben Affleck? Good, that's only going to make "Gone Girl" even better. Affleck the Director has made up more ground in recent years than Affleck the Actor, but the complex role of Nick Dunne should change that.

Here, Affleck is able to disappear into a role, while keeping around some of the baggage that has made people unfairly critical of him. Nick is handsome, seems smart, but we don't know whether we like him. There's something off. That "something" gives "Gone Girl" its ability to keep its balance on the edge of a knife.

3. Rosamund Pike's performance is all-time.

I'm going to keep this vague. I won't say why or how or what kind of performance Pike gives in "Gone Girl," but I will say that it is easily one of the best of the year, and it's absolutely going to be one we look back on years from now.

I'll leave it there... for now.

4. David Fincher will convince you only he could have made this movie.

While it's probably his least showy film in terms of technique, "Gone Girl" still has all of the signature precision that Fincher brings to his work. At two and a half hours, this isn't a short movie, but there's not an ounce of fat on it. It's technically masterful, but you were expecting that, right?

5. It's funny as hell.

But in a very bleak way. I should probably mention that. By the time every twist plays out, the movie reveals its true form as one of the darkest comedies to come along in a while.

6. The reasons you loved the book are there.

When Flynn sold the rights to her book, she insisted upon writing the first draft of the screenplay, something she had never done before. The result is faithful, without being slavish to the book, and captures the wicked essence of the it. We might not spend as much time unspooling the brains of Nick and Amy, but this is the same, addictive story you breezed through on the page.

7. It's going to make people mad.

And like the book, the ending is going to upset people, probably for a number of reasons. The climax doesn't play out exactly the same as it does in the book, but it's pretty damn close. That means we're about to hear many of the same debates that cropped up around the novel the first time around.

8. It's one of the best movies of the year.

Will "Gone Girl" win any Oscars? Will it even score some nominations? It doesn't matter because it's a ridiculously entertaining movie that's razor-sharp and expertly made.

"Gone Girl" opens in theaters on October 3.