Developer Guerrilla Games was smart enough to give nearly every side-activity a purpose at least tangentially related to the main quest. Helping various characters through their hardships may gain Aloy allies for future altercations, and things like completing Horizon Forbidden West's Cauldrons sometimes affect the larger world on top of giving Aloy new machine overrides. Much of it is just good worldbuilding though, and a great example is the Gauntlet Runs that establish an extreme sport reminiscent of the post-apocalyptic desert car races in Mad Max: Fury Road, or the more aptly named Death Race film series.
The overarching plot of Horizon Forbidden West sees Aloy travel into the titular Forbidden West to bring back an AI named GAIA which runs a now-rogue terraforming system. Despite the stakes of accelerated climate disasters, the Nora warrior has to content with the warrior-like Tenakth at every turn in order to reach her objectives. After the brutal Red Raids instigated by Horizon Zero Dawn's Carja united the Tenakth decades prior, a civil war threatens to tear the region apart now that Tenakth Chief Hekarro argues for peace.
Aloy visits all three Tenakth peoples during her adventure: the Desert Clan, Lowland Clan, and Sky Clan; as well as others in the region like the agrarian Utaru and technological Quen from across the ocean. Doing so gives her a wide impression of the cultures developed around what would be modern-day Utah, Nevada, and California, with the Tenakth creating Hunting Grounds and a Chess-like board game called Machine Strike. A subset of Tenakth also participate in Gauntlet Runs, with Aloy meeting this group after entering the Forbidden West just beyond the Rocky Mountains.
Gauntlet Runs are simple, with four racetracks across Tenakth territory that Aloy bests in order to receive the legendary Carja's Bane warrior bow. Seven participants mount Chargers and make their way through archway markers, with no holds barred as racers can knock each other off their mounts using melee attacks or arrows placed around each track. Additional pick-ups can be found hanging off these archways, from traps that trip up opponents to Blaze sacs that give Chargers a turbo-boost.
It's easy to see where comparisons to a film like Fury Road come in given its portrayal of brutal chases across the desert with racers pulling out whatever tricks they can to stop Max and Furiosa from leading an escape attempt. Yet, treating Gauntlet Runs like a sport is more interesting. Aloy first became famous in Zero Dawn due to her understanding of old-world technology and ability to override machines. Thus, it's a surprise when players learn Regalla's Tenakth rebellion in Forbidden West uses overridden machines (with more malicious, permanent overrides), but Gauntlet Runs show that some Tenakth - like the shamanistic Banuk - are able to harmonize with machines without technology.
All four Gauntlet Runs are the same, culminating with a difficult ride across the ruins of Las Vegas, but their conclusion presents a more interesting message. Aloy discovers the best Tenakth racer, Red Teeth, is actually her former Carja ally Nil - known for his bloodthirsty slaughter of bandits in Zero Dawn. He suggests the deadly sport is an apt replacement for killing that offers a similar thrill, and seems to respect that the war-inclined Tenakth feel the same. With Chief Hekkaro hoping to unite the Tenakth, one could imagine Gauntlet Runs evolving into a more common activity that matches the gladiatorial Arena battles housed in Memorial Grove.
Horizon Forbidden West is available now on PS4 and PS5.