Basically. It's generating the html for the game state every 200ms (regardless of the number of connected users) and pushing it down to any connected clients vi

Basically. It's generating the html for the game state every 200ms (regardless of the number of connected users) and pushing it down to any connected clients via SSE. The magic is Brtoli + SSE + a properly sized context window means it runs well even on 3G connections (you can play with this in chrome dev under the network tab throttle option).