OPCraft was built to demonstrate blockchain-related features like that, and also to demonstrate a toolkit developed by 0xPARC’s Lattice for building on-chain games. Conventional videogames are often built using game engines such as Unreal Engine that speed up the work by handling lower-level details of the programming of 3D environments and other components. OPCraft was built using software Lattice developed called MUD, an “on-chain game engine.”
Glibert and a fellow Lattice engineer, who goes by the pseudonym Alvarius, built MUD after struggling to build their own on-chain game. The name borrows an acronym for multi-user dungeon, a genre of virtual multiplayer game worlds that originated in the 1970s and inspired online role-playing games like Eve Online. The crypto-era MUD is designed to take care of tricky challenges such as keeping every player’s software in sync with the blockchain and adding new content to a game.
Eat Drain Arson
Last fall, Glibert’s team hosted a 12-week Autonomous Worlds Residency in London, where 45 participants, including Morris and Emerson Hsieh, built game prototypes using MUD. Most resembled conventional multiplayer games, in a similar vein to OPCraft, but one, named Eat Drain Arson, hinted at the opportunity for on-chain worlds to head off in new directions.
The prototype displayed a hovering, skeleton-like goblin. In the demo, the game’s creators, Arthur Röing Baer and his cocreator, who goes by the pseudonym GVN, made the goblin do simple actions like eat, start fires, move around a simple map, and gather a finite resource called sludge.
The goblin’s world—and even the point of the game—are still under construction. But it will be designed to encourage players to form cooperative groups if they want to make progress. The game’s developers, who call themselves Moving Castles, took inspiration from the online communities that form on Discord servers and Telegram group chats. They hope the game can incubate collectives that exist beyond the game, such as an in-game organization that has the capability to move to another digital place or platform. “You start in a constrained world that facilitates the emergence of it, but it’s not constrained by it long-term,” says Baer.
As well as trying to prove out new approaches to gaming, experiences built on MUD are also pushing the boundaries of blockchain technology. The creators of Ethereum originally promised a “world computer” that could run anything, including games, on the decentralized network powering the system. That would provide an alternative to conventional, centralized cloud computing and make services resistant to being shut down.
The downside is that running software on the blockchain this way is currently slow and expensive. OPCraft made use of a cryptographic system called a “rollup,” which combines many individual transactions and periodically links a bundle of them onto the blockchain.
Lattice partnered with OP Labs, a startup developing rollup technology, for the OPCraft demonstration. The game, which had more than a hundred players active simultaneously, was a “stress test at the most realistic but also the most innovative level,” says Annie Ke, head of protocol partnerships at OP Labs. She hopes that blockchain games can demonstrate how rollup technology could make blockchains cheaper and easier to use, making ideas like mainstream decentralized financial services and even more general-purpose applications, like blockchain-based organizations, more feasible.