The Touryst is definitely a departure for Shin'en. We're used to seeing racing games and platformers from them, but why did they take on an adventure? Shin'en explained to Nintendo Life in a recent interview.
For ages we wanted to do an adventure game. We already had done several prototypes in the past, but we felt like we would need a real fresh setting to deliver something unique and unexpected. One of our prototypes back then was located on a small lush island, and we made jokes how nice it would be to go on vacation there. And that was the perfect idea! Making a game about being on vacation, but a vacation that goes strange.