It might be worth adding a more classical, operational undo / redo system for Gaia when running in Imperative mode. The existing snapshot-based undo / redo would continue to exist and be used in Functional mode, and it will uniquely have the ability to undo / redo gameplay, unlike the operational system.

I did once experiment with using manual entity divergence to emulate this functionality partially in Imperative mode, but couldn't get it to work. Not sure if that's relevant, tho.