Cinderbelt

Cinderbelt is a top-down 3D space game that runs entirely in a browser tab. You start with a cockpit and a budget, assemble a ship on a grid, then fly it into a procedurally generated universe to mine asteroids, trade cargo, salvage wrecks and fight the Rust pirates. It is the kind of open-ended space sandbox that usually asks for a launcher and a 40 GB install; here it loads from a URL in seconds.

The shipbuilding is the heart of it. Cinderbelt treats your ship as one rigid body, so every part you bolt on changes how it flies: engines add thrust, cargo holds add mass, and the placement of both shifts the centre of gravity and the moment of inertia. A freighter with off-centre engines drifts through turns like a loaded truck, while a compact fighter with a central thruster feels sharp. The shipyard supports 1x1, 2x1 and 2x2 parts, nine armour shapes, mirror mode, templates and share codes, and a hull budget that scales with your cockpit tier. Mining is a skill rather than a button: aim the laser at richer veins, watch the heat gauge, and back off before the beam overheats.

The universe is deterministic and effectively endless, generated in 200x200 chunks from a seed so only your changes need saving. Sectors carry their own security level — Quiet, Guarded, Contested or Pirate — plus their own environment, sky and music. There is a real economy underneath: fuel from ice, power from reactors, tiered crafting, markets and contracts for delivery, mining, hunting, rescue, surveying and escort. Guild convoys let you trade or refuel in deep space, and restoring Guild relays can turn a dangerous sector Guarded. Combat is part-based too: shots hit the part they reach, shields absorb first, and severed sections become separate wrecks you can tow home and salvage. Pirate clans fly ships built from the same parts as yours, complete with named captains and bounties, and their Rust Fortresses make a natural early milestone.

Cinderbelt is designed by amoreo140, with the code, Blender-scripted models and code-composed music written by Claude Code agents under the author’s direction. Automated tests, a balance bot and performance budgets act as guard rails, and the project ships with an MIT code licence and CC BY art. It is early but genuinely playable, with four death penalties, a research tree, a home station and browser saves you can export. If you have ever wanted a build-your-own-ship space game that fits in a browser tab, start here — and expect to lose an evening to the shipyard before you ever leave the dock.