[For my previous designs] I was afraid to change the world. Instead, I desperately iterated upon new game mechanics, hoping to find one that fit my world better. And I rarely found one. As far as I can tell, creating a compelling new game mechanic is hard and success is unpredictable. Yet creating a functional game world is surprisingly cheap. Any idiot can copy a working game, toss some pirates on top and call it good.
Now I follow a different philosophy that better reflects these costs. Gameplay comes first and the worldbuilding flows from the dynamics of play. If, as you iterate upon gameplay you make a rule change that breaks the emotional connection with a particular world, you should feel very comfortable tossing that world aside and starting fresh. Create a world that supports the game, not the other way around.- Lost Garden: Triple Town Beta (Now with Bears)