A new Show HN project puts MUD2, one of the earliest online multiplayer games, directly in a browser tab by compiling it to WebAssembly. According to the author, much of the original C engine code remains unchanged, with some portions dating back to the early 1990s.
The page, hosted at mudgym.kingrolo.com, embeds a live instance of the game with a command input, loading the engine in the tab itself.
The examples on the site were built alongside MudGym, a reinforcement learning environment constructed around the game. Most of them are marimo notebooks that run MudGym in Python inside the browser through Pyodide.