I did something similar with Chaos[0], though it was less a game, and more of a social experiment. The basic idea is that the code lived somewhere on a remote machine as a bot that interacted with Github. The purpose of the bot was to automatically make decisions about pull-requests to its own code base, and then re-deploy itself. It was like a living organism in a way.

It initially started off as a democracy, requiring some % of "thumbs up" emojis on a PR before merging, but a few times it took a left turn when a "malicious" user was able to merge in code that gave them extra rights. And occasionally, the server would crash from a bad merge and I'd have to go fix it manually.

0. https://github.com/Chaosthebot/Chaos