#no-seam

Sandbox.PlayerController's WalkSpeed / RunSpeed / DuckedSpeed / Speed are private serialized [Property] fields, so an external component can't cleanly scale player move speed (e.g. for a slow/root effect). WishVelocity is public but recomputed every fixed-update, so writing it is order-dependent. Swap in or subclass a controller that exposes a public knob.

The game-reachable engine surface has no scene/global time-scale multiplier — Scene.TimeScale does not exist, and the only TimeScale anywhere is on ParticleEffect. Sandbox.Time is read-only. A slow-mo / fast-forward feature must scale each system's own Time.Delta reads, or expose a hook for a future native mechanism.