We've been working on the mechanics of Alter/Ego for a good long while, now. We knew that what we wanted to do was create a system that simulates combat between two people in a fast-paced, simple card game with enough depth to be fun for a long time.
We knew that we were going to have the bulk of the game take place in an "alternate reality" where you (the real you) were linked with a version of you in the alternate world. A friend of ours, very early on, mocked up the image you've seen all over the website, in order to give our multiverse idea some visual form.
But since that one image, we haven't thought too much about the world. I'd had this image of some of the chase/fight scenes from the Bourne Ultimatum as a backdrop for how combat might look - but I knew that we'd eventually work with other people, and that collaborating on the lore would be better than if I tried to bang it out myself.
One of the things I really like is that in both writing and game system design, if you set up enough initial constraints correctly, questions just answer themselves. We were missing some of the initial conditions for the lore, but Sean had some input that solidified one thing about the style, and one thing about the game design, and from there, things just started falling into place.
The last piece took a little bit of thought - what is the one thing in the alternate world that "split" it from our reality? If everything else is the same, what one triggering event created everything that's different about this world? Well, we're in the midst of a huge drought in California, and it definitely makes you think about how things might go from here.
Once we found that moment, everything else began to fall into place. What were people fighting for? How were they fighting each other and why? If we wanted to make something that wasn't violent, but was still centered around person-to-person combat, how would we do that? How would we differentiate our character classes & customization options? How does the alternate reality communicate with us, and why?
In the span of just a few hours, a lot of things came together - and I think a good sign for this sort of thing is that once you start thinking about it, everything else makes sense, and you want to keep thinking about where the stories can go. How it fits together in your game. What these people look like and how they live, and how those things will be revealed over time to the player - particularly in what is at least at the start, an asynchronous multiplayer game.
But this stuff coming together was everything I love about working on games with a team. Input that forces you to reconsider your initial assumptions. Collaboration where the ideas get better every person they bounce off of. That bubbly, zingy, "crackle" when an idea is gestating and creating excitement faster than you'd imagined it would.
The mechanics influenced the art, the art influenced the mechanics, and it all ties together with the lore & story. Before yesterday, the game was good, but abstract. Now it has a form. And that's just really, really exciting.