SPOILER ALERT! If you haven't read "Gone Girl," steer clear of the below. If you have, well, prepare yourself for the missing ingredients or compare your book vs. movie notes.

Die hard "Gone Girl" fans, get amped up: the movie is finally out in theaters.

But don't be surprised to see some changes in the onscreen adaptation of the beloved Gillian Flynn book. Despite the fact that Flynn wrote the screenplay for David Fincher's new film, there are a few small plot twists that didn't make the cut.

1. In the book, Amy and Nick don't see each other again for over eight months following their romantic meeting at a party in New York. (They randomly run into each other in the street.) And while the release party for the "Amazing Amy" wedding story is in the film, the event differs from how it's portrayed in the novel. Instead of Amy sulking over her life as a single woman, Nick proposes to Amy in front of reporters after two years of dating.

2. One section of Amy and Nick's anniversary treasure hunt is completely missing from the film: Nick's trip to Hannibal, Missouri, aka Mark Twain's birthplace and a place Nick took both Amy and his mistress, Andie. Here, Nick finds a letter from Amy in which she showers him with compliments and brings up fond memories. Later, the police find Amy's purse, casting more doubt onto Nick's innocence in her disappearance.

3. For the movie, Flynn cut out all of the stuff about Amy pretending to be grossed out by blood and needles. So instead of just cutting her arm and letting it pool all over the kitchen floor, like she does in the book, Amy drains her blood with an IV before using it to set up her "crime scene."

4. Tommy O'Hara is one of Amy's ex-boyfriends, but his story varies greatly between the page and screen. In both versions, Amy accuses Tommy of rape and has him arrested. In the book, Amy drops the charges, because the assault never happened (she made it up); in the movie, Tommy pleads down to another, lesser charge. Tommy tells Nick he's now legally obligated to identify himself as a sexual offender.

5. The (sort of) important scene where young blogger named Rebecca interviews Nick at The Bar and records him saying he loves and misses Amy -- as a way to sway public opinion back into his favor -- was not in the film.

6. There are some real missing women in the "Gone Girl" movie: Desi's mother, Tanner Bolt's wife and Hilary Handy -- a former high school friend who Amy duplicitously said stalked her -- are all MIA.

7. Nick's father, Bill Dunne, has an almost non-existent role in the movie. In the book, he pops up a lot, both in person and in Nick's inner monologue. (Nick doesn't want to end up like his distant, unloving dad.) In Fincher's film, Bill is only seen once at the police station. Meanwhile, Amy's parents, Rand and Marybeth Elliot, are also much smaller characters in the movie.

8. The movie skips Andie and Nick's breakup scene, where she bites his face. In the book, that kind of acts as a trigger for Andie to hold a press conference and reveal their affair. In the film, the press conference happens out of nowhere (though Tanner has already told Nick that Andie will eventually talk no matter what).

9. Desi's death is far more gruesome in the movie. Instead of drugging him with a martini laced with sleeping pills and then slashing his throat, Amy murders Desi after the climax of their intercourse.

10. The movie cuts the last tripwire of Amy writing in her diary that Nick maybe poisoned her with anti-freeze. In the book, Amy goes so far as to save the vomit in a box of Brussels sprouts (yes, really) in the freezer, so she can get Nick on attempted murder charges if he turns on her. Nick, however, finds the vomit and throws it out.

"Gone Girl" hits theaters Oct. 3.

11. Instead of writing their respective memoirs like they do in the book, the film versions of Nick and Amy do a television interview with Ellen Abbott. Nick, it seems, is prepared to tell Ellen and the national television audience all about Amy's crimes, but when Amy reveals she's pregnant -- she has used Nick's frozen sperm to impregnate herself -- he assaults her and then relents to staying with his wife.

12. Viewers don't see Amy's pregnancy develop in the movie, despite the fact that the book ends the day before the baby's due date. Sorrrrrry.