Is there anything like this? Something like Roblox, but rather than using a central server, using a network of decentralised servers with different self-hosted instances (a bit like the fediverse, but for online multiplayer games)
If there’s nothing like this, how difficult would it be to start something like this myself?
edit: Or maybe something like Scratch, where you’re not tied to a specific movement system and can program whatever kind of game you want?
A program that covers all kinds of games is going to be challenging due to sheer variety there would be. You could build a specialised protocol for a specific genre of games, but I think at that point, it would make more sense to build your own game, and use Fediverse identity to identify the user.