By focusing on Niflheim alone, the movie distracts less attention away from Mickey 17’s themes about idenтιтy. Changing Niflheim’s backstory also strengthens Marshall’s motivations in a way that makes him a better foil to Mickey Barnes. Marshall and Mickey both left Earth to escape from their past, but Marshall is pretending to have his sense of self all figured out whereas Mickey barely even started looking for it until Mickey 18 was created. This juxtaposition between the characters isn’t half as strong in the book, thanks to Marshall’s much more traditional role as one of many colonial commanders.

8

Ylfa Is A Completely New Addition To Mickey 17

Toni Collette’s Character Was Originally An Entire Planet

Although Mickey7 contains zero references to Marshall’s wife Ylfa, Mickey 17 does use one particular detail from the novel to flesh out her character. One of the colonies Mickey researches in the novel is New Hope, the birth planet of Nasha’s parents. It’s established that New Hope failed when the planet’s firstborn citizens waged civil war against the original colonists, leaving for Mickey’s home planet of Midgard after ensuring the remaining colonists lacked the infrastructure to survive.

The inciting incident for this was a disagreement over whether New Hope’s native species were sentient enough to deserve protection or delicious enough to be treated as a delicacy. While Ylfa’s food obsession plays a major role in the debate over the creepers’ sentience in Mickey 17, having an entire planet doomed to death over the issue would have been a bit too outlandish to believe. Channeling New Hope’s story into a single character personalizes the underlying issues, making them much easier to stomach while also providing the film with one of its most unique characters.

7

Mickey 17 Tones Down The Book’s Religious Overtones

The Movie’s Political Themes Are More Broadly Accessible

There are a couple of references to Marshall’s religious backers in Mickey 17, but the film never provides much detail. Bong Joon-ho made Marshall a caricature of dictators in general, and he appears to largely use the church as a tool to unify the colony under his command. This rings true for numerous controversial political leaders, but the film’s political satire might be less broadly effective if Marshall’s church felt too much like it was lampooning one particular religion. In Mickey7, however, Ashton includes multiple religious characters and provides a fair amount of background on their faith.

Niflheim’s religious characters all follow a seemingly Judeo-Christian belief system Mickey7 refers to as Natalism, which teaches that only a person’s original body can possess a soul. Natalists are established as extremely hypocritical, to the point that literally every woman in the colony sleeps with Mickey after his first regeneration renders him forbidden fruit. While this is a hilarious reveal, it also casts the book’s religious characters in an intentionally negative light. Keeping their religion vague in Mickey 17 allows religious viewers to still appreciate the film’s commentary on Marshall’s hypocrisy without taking it as a personal attack.

6

Mickey’s Backstory Is A Lot More Interesting In The Film

He Originally Became An Expendable For More Traditional Reasons

In both Mickey7 and Mickey 17, Mickey’s primary reason for joining the Niflheim expedition is to get away from a dangerous loan shark named Darius Blank. However, the way Mickey runs afoul of Darius differs wildly between stories. In Mickey7, Mickey places a series of losing bets against his athlete friend Berto (Timo in the film). After being tortured with a device that causes untold agony, he joins the colonization mission as an Expendable because it’s the one position for which nobody else has volunteered yet.

Joon-ho replaces this storyline with a much more comedic flashback in which Timo and Mickey volunteer to leave Earth after opening a failed macaron store together. This version of Darius murders and dismembers those who owe him money, which raises the stakes significantly. It also serves Mickey 17’s comedic tone a lot more than the book’s torture scene, in which Mickey undergoes physical and psychological suffering described to be every bit as painful as his future deaths by radiation poisoning and medical experimentation.

5

Jennifer’s Death Doesn’t Make Mickey Look As Selfish

The Book’s Mickey Stands By And Watches 3 People Die

During the first encounter with Mickey 17’s creepers, minor character Jennifer loses her life when she opens fire and inadvertently causes a cave’s ice ceiling to crash down on top of her. Marshall responds to Jennifer’s death by blaming Mickey, claiming there’s no reason a valuable member of the colony should be ᴅᴇᴀᴅ when they had an Expendable in their sortie. This same conversation occurs in Mickey7, but the book actually makes it much easier to understand Marshall’s point of view.

This conversation happens in Mickey7 after Mickey’s ᴀssigned duty with a few security staff and a biologist. In this version, creepers attack and kill three members of their sortie while Mickey prioritizes his own survival. Since the book has already gone into conversations about the Ship of Theseus and whether future iterations of Mickey are technically the same person, his fears aren’t entirely without merit. But since Mickey 17 doesn’t introduce these idenтιтy issues until after Mickey 18’s introduction, having Jennifer die as a result of her own mistake makes it easier to side with Mickey against Marshall’s criticisms.

4

Timo Provides Mickey 17 A More Interesting Secondary Conflict

Mickey7’s Counterpart Is Villainized Over A Simple Lie

The payoff for Berto’s betrayal in the book is that Mickey learns he’s been lied to before, revealing that the creepers once took Mickey’s body apart and experimented on his ocular biotech implants. Mickey 17 retains Timo’s dishonesty but also makes him feel like a more tangible threat, revealing that he’s planning to betray Mickey to Darius Blank. It’s the kind of twist that could render his character unlikable, but the strength of Steven Yeun’s performance makes Timo a thoroughly enjoyable side villain.

3

Kai Katz Is Way More Likable Than Her Book Counterpart

The Novel’s Cat Chen Nearly Gets Both Mickeys Killed

Mickey’s love triangle with Nasha and Kai in Mickey 17 plays out largely the same way in Mickey7, albeit with a couple of major caveats. The novel’s Cat Chen partly falls for Mickey based on racially motivated empathy, explaining that she understands Mickey being fetishized by the “ghost-chasing” Natalists because she’s dealt with being fetishized herself as one of only two Asian women in the colony. Much like in Mickey 17, their relationship never actually progresses far before she catches Mickey and his multiple sharing a bed with Nasha.

This is where their paths diverge, as Mickey 17’s Kai ultimately chooses not to betray Mickey. Not only does Cat betray him instantly, but she even offers to become the next Expendable, so Marshall has no reason to keep either Mickey alive. It’s her duty as a security officer, and she’d risk getting thrown down the corpse hole herself if Marshall found out she was hiding knowledge of multiples, but volunteering to replace Mickey goes so far overboard that she’d be a lot harder to sympathize with if Mickey 17 hadn’t changed her character in the ways that it did.

2

Manikova’s Backstory Is A Lot More Believable In Mickey 17

The Lead Scientist Originally Tried To Take Over The Entire Universe

If Mickey 17’s dream sequence seems surreal, it’s nowhere near as bizarre as Mickey7’s explanation for how bio-printing scientist Alan Manikova led to multiples becoming taboo. After perfecting the tech that allows Expendables to upload their memories, Manikova committed genocide against a colony called Gault to harvest their protein into a full colony of his own multiples. Manikova created so many multiples and became such an immediate threat to the known universe that a neighboring colony eventually grew frightened enough to simply eradicate Gault altogether.

This is a wildly fun story to read in the book, but even a director like Bong Joon-ho would struggle to relate that story in a way that doesn’t sound borderline cartoonish. Three Manikovas simply killing a few homeless people in Mickey 17 is down-to-earth enough that it’s believable for the world established by the film, yet it’s still extreme enough that it’s understandable why Earth would take issue with a scientific process that once gave a man access to legally unprecedented murder alibis.

1

Mickey 17’s Ending Allows The Movie To Stand On Its Own

The Book’s Story Feels Incomplete Without Knowing There’s A Sequel

Of all the changes between Mickey7 and Mickey 17, arguably nothing was altered as drastically as the ending. Mickey7 seems to end with the creepers killing Mickey8 and stealing his antimatter bomb to achieve mutually ᴀssured destruction against Niflheim, but this is actually a ruse by Mickey7 to ensure that Marshall has to keep him alive as the humans’ only diplomat capable of communicating with the creepers. This sets up the events of the second book, but Mickey 17’s sequel hook is nonexistent.

This ultimately serves the movie well, as the story feels more complete regardless of whether Bong Joon-ho ever directs a follow-up. Marshall is no longer a threat, and the humans have achieved true peace with the creepers rather than a cautious truce. The book’s ending feels more like something from an Ender’s Game novel, in which interspecies alliances are generally a bit precarious at best. It’s a familiar trope to fans of sci-fi literature, but those who simply want a movie with a complete resolution should find that Mickey 17 scratches that itch perfectly.