Ruinweavers

Ruinweavers is a browser game built around interacting elemental spells. I'm exploring how physics and a shared world can support combat, alone or with another player. The current prototype has four fights connected by shared route choices, upgrades between encounters, and a final boss.

Spells that change the world

Ember adds heat, Tide wets targets, Gale applies force, and Stone changes structures. Their effects operate on shared properties: heating a wet target produces steam, while weakening a structure makes a later impact more damaging. In co-op, one player's spell can set up a reaction triggered by the other.

The magic rules work on the target's state, so these interactions don't need a separate rule for every pair of spells. Rapier handles collisions and physical movement; Three.js renders the world. The simulation is separate from rendering, which also lets me exercise the combat rules in repeatable tests.

Keeping co-op movement responsive

One player's browser runs the shared simulation and sends updates over WebRTC. Waiting for each update would make the other player's movement feel delayed, so their browser previews walking immediately, then reconciles it with the host's position by replaying inputs the host hasn't acknowledged yet.

That prediction is deliberately limited to walking. Hits, health, spell outcomes, and dodges remain the host's responsibility. Other characters move smoothly between received snapshots. This keeps the responsiveness work separate from deciding what happened in combat.

The game is still a prototype. The repository includes automated tests and recorded gameplay used to compare room layouts and spell builds as it develops.