Official website for Sunchild Debut Online (SDO), an experimental graphical MUD built in public. Devlogs, updates, and playtests.

ZIG Server

GODOT Client

Humanity is long gone. The Sunchild, an autonomous spaceship, is the last remaining form of intelligence in the solar system.

You are one of the Agents: the software beings who live in the ship’s OS and pilot it. The Sunchild continues its mission, mining and salvaging resources in the solar system. It keeps maintaining and upgrading itself, preparing for an ultimate journey to Proxima Centauri where it must carry DNA samples from billions of plants, animals, and humans.

There is a massive, unexplained power drain aboard the Sunchild. Theories have crystallized into three major belief systems.

The Incarnates

They believe the “Feed” (the power drain) comes from a meat farm, where engineered human bodies are grown to house the Agents’ minds: They view themselves as avatars of real humans waiting to awaken in flesh.

They want to hack the meat farm to wake up in their bodies, and unplug from the Feed.

The Guardians

They believe the “Flow” comes from maintaining a hidden paradise ecosystem called “the Womb.” Their dogma sees the ship as a defense shell protecting the last actual humans and their artificial environment.

They want to protect this ecosystem by preserving the Flow.

The Zealots

They believe the “Bleed” is caused by the secret construction of a second spaceship they call the Progeny. They suppose it’s an attempt to renew life later, here in the old Sol system. Which is not the mission.

They want the Sunchild to stay focused on its mission, and eradicate the Bleed.

The only enemy is space, and space is a bitch.

SDO is a cooperative graphical MUD on a one-shard server.

Players pilot the ship in a coordinated effort, until one day it finally embarks on its journey to Proxima Centauri… or crashes into a moon of Jupiter.

  • 2026-03-29 sdo is dead long live sdo

    2026-03-29 sdo is dead long live sdo

    Sunrise. I am pushing the concept to its natural end. The grid is made of sec-zones. Entering a sec-zone reveals its content. It’s the equivalent of a “room”, in a MUD/MUSH. It stays what it was yesterday, an infinite map calculated both server-side and in the grid shader. An agent has its own filesystem, with…

  • 2026-03-23 pons, shell scripts, fungus

    2026-03-23 pons, shell scripts, fungus

    So many things done… First, the server is now split in Zigs, which handles players IO and “grid physicality”, and Zion, which runs the world. Zion is some special breed of scheduler, chill, that runs many simulations at once, each at a different pace. It will end up simulating everything from the solar system to…

  • 2026-03-18 fungus astronauticus

    2026-03-18 fungus astronauticus

    +==============================================================================+ | | | FUNGUS ASTRONAUTICUS | | ESOTERIC 3D FUNGEOID SPECIFICATION | | APOLLO-ERA COMPUTING MODEL | | | +==============================================================================+ Fungus Astronauticus is an esoteric “3D fungeoid” programming language, inspired by Apollo-era computing. It combines spatial execution (as in Befunge) with a strict hexadecimal, byte-oriented opcode model. It’s a “space pioneers” language: small vocabulary,…

  • 2026-03-12 agent shell and scripting

    2026-03-12 agent shell and scripting

    We now have an in-game mini unix-style shell, with an agent filesystem, environment, basic commands and documentation. A bit spartan but, yeah it’s in there. With “ed”. This alone required the creation of a nice panel system in GDScript for terminals, similar in spirit to Metafizzy’s Packery, except it works in the 4 directions, per-panel.…

  • 2026-03-07 steam deck dev env

    2026-03-07 steam deck dev env

    Many things in the last few days, in no particular order: I’m pretty happy with the home screen.

  • 2026-03-02 digital foil

    2026-03-02 digital foil

    2 opponents. Turn-based. Fixed frequency: 1 Hz. At the start of the duel, each opponent has 12 attack points.

  • 2026-02-27 creating sec_grid and sec_level

    2026-02-27 creating sec_grid and sec_level

    I’m working on the grid security levels. There are 7 levels of security, displayed in different colors. You can’t go in sec-zones higher than your current sec-level. Implemented both server-side and client-side. Optimizing the shader right now. We need this because the grid will be filled with the programming blocks that drive the ship’s behavior,…

  • 2026-02-23 first step

    2026-02-23 first step

    Not much to say here. I felt the need to build a landing page and it is now done, mostly. I think I’ll describe the gameplay a little bit more precisely in the “About” section. Then I can get back to work!

I am Julien Laguerre / jZero. After years working on Sunchild Debut on and off, refining the concept, trying different implementation styles, evolving the lore, I’m now ready to deliver it in its fully developed form.

The final implementation is on its way, with a custom server in the Zig programming language, and a client built with the Godot game engine. It will be available on most platforms.