Easel introduces a custom physics engine that handles multiplayer worlds at scale by performing incremental rollback. Instead of snapshotting the entire scene, it updates only the handful of objects that change each frame—often fewer than 30—cutting roll‑back work 30‑50×.

The engine employs a BVH for spatial indexing, keeping collision checks fast while minimizing unnecessary snapshots. Bodies fall asleep immediately after velocity drops to zero, and the system tracks balanced forces to avoid keeping inactive stacks awake.

Stepping and collision resolution receive special treatment. A new ForcefulStep routine eliminates bounce‑back without sacrificing knock‑back physics, and continuous collision detection resolves fast‑moving objects accurately by integrating positions after determining time‑of‑impact.

By avoiding full‑world snapshots, Easel now supports large, complex multiplayer games, opening the door to titles comparable to Among Us while maintaining responsive gameplay.