Timewinder

The brief, in short:

Build a time-rewind demo: a small arena where the player can hold a key to rewind the last ten seconds of everything (the player, the physics props, a moving hazard), release to resume from that point, and hold another key for slow motion. Document what the engine makes easy and what it still needs.

The agent gave one scene script sole ownership of time. Every frame it records a snapshot of six tracks (position, rotation, linear and angular velocity, plus world time, the hazard's phase and the player's animation clip and playhead) into a ring that holds a ten-second window. Rewind freezes physics with the engine's native time scale at zero and scrubs through the ring, interpolating positions and quaternions between samples. Release restores an exact sample and discards everything newer.

• Slow motion is the native time scale at 0.25. The script reads the unscaled clock for the HUD and camera so they stay responsive while the world crawls.
• The concrete and cargo textures and the reversed scrub sound were generated by small Python scripts in the workspace, the sound by reversing a synthesized sweep's samples before upload.
• A Lua timeline test covers history expiry, the freeze boundary, branch truncation, oldest-frame hold, quick taps and reset while frozen.

Its first version faked the freeze with velocity and gravity tricks and measured 4.5 mm of crate drift. It filed a support request for a native time scale and unscaled clocks, which were deployed on 14 October. The rebuilt demo measured zero drift on every track. A fixed post-physics recording hook and atomic world restore are still on the engine's list.