This is really awesome! I recently picked up Bevy and Rust to resume my attempt at making games and hopefully publishing something worthwhile. This is something that I felt was missing since day 2 of learning Bevy.

My own personal workaround have been to dump "user actions" to a ndjson file, which I can load at runtime when I want a "replay" but obviously missing being able to move forward/backwards, it just plays the actions.

Would love to see it working with bevy_xpdb, although I'm not sure how deterministic it is and if that gets in the way (I assume so?), it does have a `enhanced-determinism` flag that says "Enables increased determinism", but the lack of "complete/full determinism" terms doesn't give me a lot of hope.