The new movie version of It opened in cinemas to massive box office, breaking records left right and centre for horror movie takings, and attracting positive reviews.

Spiritually and emotionally, we reckon it's one of the most faithful Stephen King adaptations we've seen in a while, but the movie does make some changes to the source material.

Here are the ways the movie clowns around with the book. Note: spoilers are inevitable.

1. It's two separate parts

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Though it absolutely works as a standalone, the film of It that you can watch in the cinema right now is chapter one – it's announced as such at the end of the movie. While King's novel deals with two different time periods in Derry, Maine – one focusing on The Losers Club as kids and another when they return as adults some decades later – the narratives in the novel are intertwined.

This first part is only concerned with the kids; we haven't met the adult versions at all yet. Their narrative will be reserved for chapter 2, which director Andy Muschetti is going to return for.

2. The time period

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In the novel the kids are growing up in the late '50s, with the adults' narrative taking place in the late '80s. Muschetti's version has updated it so the kids' section begins in the late '80s. Cue not only comparisons to Stranger Things, but also references to New Kids on the Block and A Nightmare on Elm Street 5. The second part will then be transported to the present day (which is in fact true to the book, which was published in 1986).

3. Georgie's death

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Bill Denbrough's little brother's encounter with Pennywise, when we first meet him peeking out of a storm drain, is pretty faithful, but a major deviation is that in the film Georgie's body is never found (it is in the book).

This gives Bill a major motivation to go after Pennywise – he thinks there's a chance he might still save his brother. Doubt over Georgie's fate also enables a key moment for Bill at the end of the movie.

4. Pennywise's creatures

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The dancing clown is just one of the guises taken on by the entity that the kids know as 'It' – It is a master shape-shifter who likes to take the form of whatever scares the kids most. The movie absolutely sticks to that principle, only different things scare these '80s pre-teens compared with their '50s counterparts.

Rather than classic movie monsters – The Mummy, Gill-Man, Frankenstein's Monster, The Wolfman, etc – or a giant bird for Mike and drowned kids for Stan, It picks different reference points. While some of the gang get the same apparitions, Mike is tortured with images of his parents burning in a fire, Stan the embodiment of a scary painting.

The scene from the book where Ben melts a silver dollar, to make silver bullets for a slingshot the gang use on the creature, is also changed. Instead the Losers use Mike's grandfather's cattle bolt gun. More on this below...

5. Mike's background

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In the book, Mike lives with his dad, who is a farmer. In the movie, both of Mike's parents were killed in a fire, which Mike escaped (and he feels horrible about it). Mike is raised by his grandfather, who keeps and butchers cattle (which is why Mike has access to, and knows how to use, a bolt gun).

In the book, Mike is the one who clues the gang into the town's history. In the movie, this job falls to Ben Hanscom.

6. The fate of Henry Bowers

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Deranged bully Henry is very much a part of the film, but with slight changes. His dad is a cop, not a farmer. And in this chapter at least, we don't see him being expelled from the sewer and blamed for all the child murders that have taken place, as we do in the book.

However, there's every chance this'll be a detail included in chapter two, so keep your eyes peeled.

7. The Macroverse and the giant turtle

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Fortunately Muschetti decided not to include all that Stephen King Universe mythology about Maturin the giant turtle who apparently vomited up the whole of the universe because he'd had a big dinner (or something). In the book, Bill discovers the 'Ritual of Chüd' which allows him to enter the 'macroverse' to chat with the turtle and understand the true form of 'It' (ie The Deadlights). In the film, Bill has a Lego turtle on his bedside table and makes an offhand remark about seeing a turtle in the water when he and the Losers are having a swim. And thank goodness, that's it.

8. The weird orgy

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Another good choice from Andy Muschetti: after the kids defeat Pennywise for the first time in the sewer, unlike in the book, Beverly does not decide to have sex with all six of the boys.

In 2013 Stephen King commented on the scene: "Intuitively, the Losers knew they had to be together again. The sexual act connected childhood and adulthood."

More recently, related to the new movie and its decision to cut that bit out, he added:

"To [my previous statement] I'd just add that it's fascinating to me that there has been so much comment about that single sex scene and so little about the multiple child murders. That must mean something, but I'm not sure what."

Yeah. But you were the one who wrote it...

9. Beverly's rescue

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Points for not making Beverly have group sex to unite the group. But points deducted for the decision to have her be kidnapped by Pennywise and become a damsel in distress – the gang of boys is united by rescuing Beverly, who is suspended in Pennywise's lair. When they get her down (she floats too!), she's catatonic. Only a kiss from lovely Ben Hanscom can wake her, a bit like Sleeping Beauty. If that was a horror about a clown who eats children...

IT is in cinemas right now in the US and the UK.

From: Digital Spy