Art
I believe it is highly beneficial for a game designer to have a sound understanding of visual aesthetics like the basics of canvas space usage and the foundations of animation. To balance and implement even basic systems like a kinesthetically pleasing jump curve you have to know about animation principles like timing, spacing, and weight.
This is one of the reasons I try to improve as an artist as well as a designer and developer, and the reason why I included a small collection of my works in this portfolio.