The first installment in the Horizon video game series, it follows Aloy, a young hunter in a world overrun by machines, who sets out to uncover her past.

[14] Aloy wears a Focus, a small earpiece that scans machines to determine their susceptibilities,[15] identify their location, their level, and the nature of loot they will drop.

[20] The skill tree has three categories: "Prowler" concerns stealth, "Brave" improves combat, and "Forager" increases healing and gathering capabilities.

[21] Upgrades in each category result in more adept use of the skills learned, with "Prowler" leading to silent takedowns, "Brave" to aiming a bow in slow motion, and "Forager" to an enlarged medicine pouch.

[32] Side quests involve Aloy completing tasks, like gathering materials, coming to the aid of individuals in danger of being killed, solving mysteries, assuming control of bandit camps, eliminating criminals and more difficult machines, accomplishing various challenges at any of the five Hunting Grounds,[9][33] and obtaining an ancient armour that makes Aloy almost impervious to damage.

[15] Collectibles include vantages that offer visual information of the Old World, metal flowers that contain poetry, and old relics, such as ancient mugs and tribal artefacts.

The Banuk consists of wandering clans made up of hunters and shamans who live in snowy mountains (Wyoming's Yellowstone National Park) and worship the "blue light" of the machines.

[35] Aloy (Ashly Burch) is cast out from the Nora tribe at birth and raised by a fellow outcast named Rost (JB Blanc).

As a child (Ava Potter), Aloy obtains a Focus, an augmented reality device that gives her special perceptive abilities.

Aloy becomes curious about her origins and is told by Rost that if she wins the Proving, a competition to earn the right to become a member of the Nora, the tribe's Matriarchs might concede this information.

Zero Dawn, a project spearheaded by Sobeck, was initiated to create an automated terraforming system to eventually deactivate the Faro robots and restore life to Earth over a period of centuries.

Aloy learns that Sobeck was sent to a decommissioned Orbital Launch Base to complete Zero Dawn, located under the Citadel, the center of Eclipse power.

Inside the base, Aloy learns that Zero Dawn was a vast underground system of databases, factories, and cloning facilities controlled by a single artificial intelligence, GAIA (Lesley Ewen), and her subsystems.

Once all life had been extinguished, GAIA developed a countermeasure to deactivate the Faro robots and build her own animalistic machines to restore the Earth's biosphere.

Once the planet was habitable again, GAIA's next goal was to reseed life on Earth based on stored DNA and teach the first human clones not to repeat their predecessors' mistakes.

Aloy kills Helis and helps fight off machines before stabbing HADES and activating the master override, ending the war.

[9] Aloy travels to the "Cut," the home of the Banuk tribe, after hearing word of dangerous machines appearing and a mountain belching smoke.

She finds Ourea (Necar Zadegan) in an Old World facility that had been converted into a Banuk shrine and is housing an artificial intelligence the shaman calls the "Spirit."

They infiltrate the Old World facility built inside the mountain, where Aloy discovers that the Spirit is actually CYAN (Laurel Lefkow), a highly advanced AI designed to prevent the Yellowstone Caldera from erupting.

The team aimed to emphasise the game's exploration element by featuring a quest system, as well as including items throughout the world that can be used to craft or replenish health.

[46] In extrapolating the game world, Guerrilla turned to anthropologists and researched the formation of tribal cultures as well as how building materials would decay over a millennium.

[51][52] Burch voiced Aloy,[51] whose likeness was portrayed by Hannah Hoekstra,[53] and motion capture was performed by Amanda Piery in London.

Following an auditioning process in 2014, Burch was called in to do the E3 2015 trailer and proceeded to work on the game for two years in Los Angeles, providing facial motion capture as well.

[54] The game's soundtrack was composed by Joris de Man, the Flight, Niels van der Leest, and Jonathan Williams, with vocalist Julie Elven serving as the primary performer.

For the tribal theme, they experimented with bows on piano wire and resonator guitars (with layered tracks of harmonicas on top of the latter) and playing cellos with plectrums or the back of a bow to convey how contemporary instruments would be played by someone to whom the instruments were unknown; de Man also used a contrabass flute and made synth pads from blowing on a Thai bamboo flute, noting "distant pads and ambiences, and wide, spread out chords seemed to work well".

[72] New Game Plus, an Ultra Hard difficulty mode, additional trophies and aesthetic features were introduced with a patch released in July 2017.

[80] Destructoid's Chris Carter commended Ashly Burch and Lance Reddick for their performances, with the character of Aloy receiving credit for maintaining a "captivating" and "interesting" consistency in the narrative and action sequences.

Considered the most powerful part of the game, the Focus feature gained approval for complementing the combat in a way that "forces you to become a hunter".

[88] Giant Bomb's Jeff Gerstmann declared Horizon Zero Dawn as "a near-perfect story" with a satisfying conclusion, and emphasised that it contained substantial depth.

[95] Colm Ahern of VideoGamer.com wrote in his verdict, "Destroying large robot beasts while frantically switching between weapons is intoxicating, but the strength of Horizon Zero Dawn is in Aloy's engaging quest to find out who she really is".