History Film / MortalEngines

* ChekhovsGun: Hester Shaw's necklace, which was given to her by her mother, [[spoiler:contains the Crash Drive needed to shut down MEDUSA during the climax.]]

In a post-apocalyptic world, entire cities have been mounted on wheels and motorised, and prey on one another. Tom Natsworthy (Sheehan), a sixteen-year-old Londoner, gets in the way of an attempt by the mysterious masked woman Hester Shaw (Hilmar) to kill Thaddeus Valentine (Weaving), a powerful man she blames for her mother's murder, and both Hester and Tom must fend for themselves.

** In the books, there's no indication that Pandora Rae a.k.a [[spoiler:Pandora Shaw - Hester Shaw's mother]] and Anna Fang knew each other or had even met. In the film they were close friends and allies to the point where Anna spent years trying to find [[spoiler:Hester]] after Pandora’s death.
** In the book, Tom and Bevis don't know each other and have no interactions with each other. In the film they appear to be casual acquaintances on a first name basis.

* AllHailTheGreatGodMickey: A brief gag shows that among the London Museum's artifacts is a set of "American deities" that are quickly revealed to be large [[WesternAnimation/DespicableMe Minions]] figurines.[[note]](In the book, they're actually Mickey and Pluto, but since the movie wasn't made by Disney, they didn't have rights to the characters.)[[/note]]

* PragmaticAdaptation: The original novel had a brief mention of plastic idols of [[Franchise/MickeyMouse "Mickey and Pluto]] the animal-headed gods of lost America" in the London History Museum. The movie being made by Universal replaced them with plastic statues of [[WesternAnimation/DespicableMe The Minions]] - identified in-universe as ancient deities, due to the fact that Creator/{{Disney}} own the former characters.

** The Museum has two statues of "American deities"... [[TakeThat which are]] [[WesternAnimation/DespicableMe Minions]].

* VisionaryVillain: Valentine's absolutely right when he states Municipal Darwinism is unsustainable in the long term (something gone into in more detail in the books). He plans to use MEDUSA to blast London's way into Shan Guo to take their more more plentiful resources instead of scavenging other cities.

* FrankensteinsMonster: Shrike the undead SuperSoldier. The Stalkers are regarded with abhorrence by Tom as some kind of MadScience UltimateEvil from the ancient world. Yet like the original monster Shrike has a gentle side that causes him to protect Hester as a little girl. [[spoiler:Also he wants to create a companion like himself, though in this case a child, not a bride.]]

** The airships are ''vastly'' different in design and operating principle than the original concepts; in the novels, they're quite literally ZeppelinsFromAnotherWorld, with large gas envelopes with small control cabins and underslung engines, but in the film, they resemble winged [=VTOLs=] powered by futuristic-looking engines, which ostensibly also provide lift to the vehicles as well.

* AdaptationDeviation: Notably, the ending isn't as dark as that of the book: [[spoiler:London isn't destroyed by the misfiring MEDUSA, and while it's depowered by Tom destroying its reactor, the population survives. Also, Katherine isn't accidentally killed by Valentine in the fighting surrounding MEDUSA, and survives to lead the Londoners in making peace with Shan Guo.]]