I'm glad someone else thought of that and finally implemented it.
I interviewed with an embedded tools company in the 90s and independently came up with the idea for this during the interview to try to impress them. It didn't work. I immediately forgot about the idea until now.
My thinking was that if you were simulating an embedded device you could record all state changes, and then be able to step forwards AND backwards (or jump to any earlier point).
Glad you get to see your idea existing - quite a few engineers of a certain low-level inclination tell us they had imagined (or tried) doing this.
There were academic implementations of this sort of thing around quite a while ago - and VMware's record/replay tech - but these days we have Undo LiveRecorder, rr / Pernosco, Microsoft's WinDbg / TTD, replay.io
My thinking was that if you were simulating an embedded device you could record all state changes, and then be able to step forwards AND backwards (or jump to any earlier point).