InfinityArcs multiplayer staging

Test build. Not linked from the site. Rooms here are real and run on Cloudflare.

• Orb Dash orb-dash@0.1.0 · online 2-4 players

How to test

1. Open the game on two devices (or two browsers).
2. Private room: one player taps Play online → Create room and sends the code or link; the other taps Join by code.
3. Open multiplayer: both tap Quick play. Alone? A computer player fills the seat after a few seconds.

Room server check: open /mp/rooms/ABCDEF. It should show {"error":"bad_origin"}. That is correct: the room server answers, and refuses requests that do not come from a game.