MudGym Brings MUD2 to the Browser via WebAssembly as a Reinforcement Learning Environment

A browser-based demonstration is running MUD2, one of the earliest online multiplayer games, compiled to WebAssembly so that it executes directly inside a browser tab. According to the project's author, much of the original C engine code remains unchanged, with portions of it dating back to the early 1990s.

The author says the examples were built alongside MudGym, a reinforcement learning environment constructed around the game. Most of the examples are marimo notebooks that execute MudGym itself in Python within the browser, using Pyodide.

The embedded engine view on the page displays a tick counter, shown as "TICK 00000" during loading, together with a field for entering commands.

The project was shared as a Show HN post on Hacker News on 12.11.2026 and is available at mudgym.kingrolo.com.