Bringing mechanics and combat used reserved for action games, dual stick shooters, and such to the open world genre. Basically leveraging their FPS experience
As I said before, usually enemies in open world games, especially non-fantasy ones, are guys categorized by the weapon they use. The sniper, the heavy with a flames thrower or mini gun, the up close shotgun guy, the regular enemies with pistols or machine guns. You can defeat them all with firing indiscriminately
Horizon plays more like a Vanquish or Enter The Gungeon. Enemies with 7, 8, 9, different attacks for different distances, melee or ranged, with precise weakpoints that require positioning and careful aim to hit, and telegraphed attacks and aggressive movement that encourages dodging until you have the time and space to return fire.
The machines are also driven by AI and interact with each other outside of your presence. Given everything we've seen and read, it's the closest thing to Rain World in depicting a dynamic ecosystem, in the AAA space,