2017 was an interesting year in gaming. The Nintendo Switch was released to massive acclaim, owing in no small part to the success of launch titles like Breath of the Wild and Super Mario Odyssey, and it was also the year Guerilla Games released their long-awaited new title, Horizon: Zero Dawn. Immersing players in a world overtaken by machines in a post-apocalyptic setting, the backstory of how Earth came to be this way was a major factor in the game's overwhelming success.
Even though it has been three years since Horizon was released, there are still aspects of the story that have yet to be explained, which may be revealed in the upcoming Horizon: Forbidden West, but some of the supposed missing pieces can be found among the numerous audio and text logs found by Aloy in the game.
10 Why Are The Human Tribes So Primitive?
It may seem strange at first glance that such primitive cultures can live alongside self-aware machinery that is modeled after real-world creatures, but the answer as to why this is the cast isn't fully revealed to Aloy until near the end of the game. Ted Faro, the man responsible for the Faro Plague and the extinction of Earth, took it upon himself to ensure humans couldn't make the same mistakes he did.
And he believed that the only way this could happen is if they didn't have the knowledge and wisdom of a modern Earth. APOLLO, the A.I. designed to educate the new human race once Earth had been reborn, was tampered with and ultimately destroyed by Faro, erasing his past crimes and ensuring humanity couldn't make the same mistake twice.
9 Why Are There Robot Dinosaurs?
This aspect of GAIA, the commanding A.I. for Project Zero Dawn, was only shown in a throwaway line while interacting with Dr. Sobek. During their early days together, GAIA was taught about the different creatures that walked the earth and expressed her regret that some animals, namely the dinosaurs, were wiped out before she had a chance to see them in real life.
GAIA expresses to Sobek that she wishes they could have had a chance to live a little longer, and her mindset ended up influencing the machines that would be created by the A.I. HEPHAESTUS.
8 Why Are The Machines Hostile Towards Humans?
As the cloned humanity left their bunkers and began to repopulate the earth, they were at a huge disadvantage without the education that should have been provided by Apollo. As such, they had no idea what the purpose of the machines was and began to hunt them down for parts. This was seen as an act of aggression by Hephaestus and resulted in her changing the programming of the machines.
Once the subordinate A.I.s became freed of GAIA, HEPHAESTUS took it upon herself to ensure the machines could protect themselves against the humans hunting them, which also resulted in the creation of newer, deadlier machines like the Stalkers and Thunderjaws.
7 Why Is The Wildlife So Limited?
While there are some smaller life forms that wander the world, these are mainly limited to fish, birds, and boars, while the bulk of other animals are made up of the machine variants. While this could come down to the fact that this Earth is relatively new and populations haven't had time to grow back yet, it also has to do with the number of genetic samples that were taken before Earth went extinct.
During one of the video recordings Aloy watches, it is mentioned that many of the samples that were intended to be collected weren't able to be taken in time, as the Faro Plague had wiped those animals out before the scientists had a chance to keep them from going extinct.
6 Who Created The Metal Flowers?
One of the many collectibles in Horizon is the mysterious metal flowers that bloom across the world. While it was at first assumed they were simply designed to help germinate new flora when Earth was terraformed, Kudiv, a merchant, reveals that they didn't appear until after the Derangement, the event that freed all of the subordinate A.I.'s from GAIA's control.
This implies that DEMETER, the A.I. responsible for plant germination, has taken it upon themselves to create these metal flowers for an as of yet unclear purpose.
5 Why Was Rost An Outcast?
One of the biggest mysteries in Horizon surrounds Aloy's surrogate father, Rost. For the majority of the story, he is known to be an outcast of the Nora people with no clear reason as to why. When his backstory is finally revealed, it paints a heartbreaking picture of his past.
After an attack on Mother's Vigil by Outlanders, Rost's six-year-old daughter is kidnapped and her mother killed in the assault. She is later killed by the attacking party, and Rost is made a Death-Seeker to enact his revenge on the ones who took his family from him. He succeeds in getting his revenge, but at the cost of his previous life withing the Nora tribe.
4 Who Is Sylens?
Initially introduced as a voice speaking through Aloy's Focus, Sylens is a mysterious character with only some hints as to his origins. Possessing an overly curious mind, Sylens, like Aloy, found a Focus deep within an old ruin, which led him to find a broken down Titan containing the A.I. HADES. His life before this time isn't spoken of much, but there are some hints that he is associated with the Banuk tribe.
As he states to Aloy towards the end of the game, her ability to override machines is similar to Banuk shaman rituals, implying he is knowledgable of their secretive practices. He also has machinery integrated into his body like all other Banuk, though passing comments from the Banuk themselves seem to imply that he is unwelcome in their tribe for some unknown reason.
3 Why Did Faro Kill The Zero Dawn Team?
One of the last pieces of the puzzle Aloy witnesses is the revelation that Faro not only tampered APOLLO, but also caused the deaths of everyone working on Project Zero Dawn. As the project expanded, Faro grew increasingly paranoid and afraid of what the future humans would think of him, as he was held solely responsible for the extinction of Earth.
Knowing that the Zero Dawn leaders would be able to rebuild APOLLO when he destroyed it, the only course of action in his mind was to kill them off as well, to prevent the world from ever knowing what he had done in the past.
2 What Happened To The Odyssey?
As briefly mentioned around halfway through the story, a secondary measure was undertaken to prevent humanity from going extinct, an ark in the form of a space shuttle called the Odyssey. While the Zero Dawn team viewed it as nothing but a way to keep humanity from losing all hope, they were kind enough to give the Odessey an alpha version of APOLLO.
Considering the lengths Faro went to in ensuring APOLLO would be destroyed, it is heavily implied that he is responsible for the destruction of the Odyssey in its failed launch as a part of his greater plan to erase his crimes from history.
1 Who Freed The Subordinate A.I.s?
The big question left hanging during the ending of Horizon is by Sylens, as he recaptures HADES in a lantern and enquires who freed him from GAIA's control. While there is no definitive answer as of yet, it is known that Faro had backdoor access to many of GAIA's subroutines, as well as having access to most of Project Zero Dawn.
Although he would be long since dead, it is entirely possible that this was an attempt to ensure his legacy wasn't known to the rest of the world, even after the lengths he went to before the extinction of humanity.