Horizon: Zero Dawn turned out to be a very successful game, garnering rave acclaim and selling 7.6 million copies in a year, upon its launch on the PS4 last year, but its development was a process of trial and error for Guerrilla Games, who had, after all, never developed an open world RPG before.
For instance, even though the game had been received well during its E3 2015 debut, it turned out that when playtesting for it began, users were pretty unhappy with the game, calling it boring. Continued playtesting allowed Guerrilla to address the problems, and make it more compelling.
That wasn’t all, either- while Horizon: Zero Dawn is open world, the actual game world isn’t that massive, compared to other open world games such as Breath of the Wild or The Witcher 3. That was not always the case, and originally, the game world was bigger than GTA, Skyrim, or World of Warcraft. This made the developers lose focus, and in the end, the world size was pared back.
The end result is Horizon is a damn good game- one you can play right now exclusively on the PS4.