Co-op has always been part of Nightfall Survivors: rooms with a 4-letter code, up to eight players, cards for each of them and a vote to pause. In the Unity version, it got a dedicated C# server.
The same simulation on both sides
This is where the migration pays off. The game simulation is pure C#, with no Unity, so the server runs exactly the same code the game runs in solo mode. The server is the authority: it advances the match 60 times per second and sends the state to players about 30 times per second, compressed and lean.
On the player’s side:
- the game interpolates what arrives on the server’s clock, so nothing teleports;
- your hero responds instantly, with local prediction that uses the simulation’s own movement code;
- the world is rebuilt from every snapshot, and all effects, sounds and animations work just like in solo.
What already works
A lobby with a code to copy, hero and difficulty selection, ready and start, cards per player, Execution and the Void Implosion in co-op, pause voting, spectating when you fall and the death cam: a slow-motion replay of the last second or so, with “Killed by” at the end.
What is left
The server is built and tested but not live yet: it still has to be installed on the game server, next to the current one, and hooked up to accounts and the leaderboard, which depend on phase 7. When the Unity version’s online co-op is open to everyone, the news will be posted here.
