Mathematica Playtest is Available
Sure enough, several months later, I had an idea that I decided to incorporate into Mathematica. That's not to say that the game is anywhere near done, or works, or anything like that. But I do now have a playtest version.
To participate in the playtest, visit the forums here and download the latest version.
Past posts on Mathematica are here.
Update: Apparently there's a problem getting the playtest doc in some browsers. I think I've fixed it.