Speak of Hayami reminds me of the art style I used to apply.
At that time, I was trying to make everything as realistic as possible visually, but it was too hard, so I made it a bit more cartoonish. It was a good time, though my marketing knowledge and inadequate skill set failed the project.
If I ever have the chance to relaunch a similar project as Hayami's, I would want to learn Houdini and make everything crazily realistic to see how I can apply the PBR rendering and procedural modeling I learned from TA's work to practice, but it always hard to find time to do more.