Multiplayer has been the single most requested feature for Teardown ever since before its initial release. Synchronizing physics over the network is already known to be hard, and on top of that we have a completely dynamic, destructible world with full modding support. For a long time, we considered the whole idea unrealistic.

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The developer behind Teardown shares the full story of implementing multiplayer in a game with a completely destructible, physics-driven voxel world. The post covers the core technical challenges: achieving deterministic destruction using fixed-point integer math and a command stream, combining reliable and unreliable network channels, handling scripting and modding compatibility, synchronizing in-game terminals via delta-compressed draw commands, a painful multi-month codebase merge, backwards API compatibility, and a late-join solution based on replaying the deterministic command log. The author reflects that the result is not elegant but represents enormous engineering effort, and hints at a cleaner approach being explored in a new engine.

The unlikely story of Teardown Multiplayer