The Digital Life and Times of a Simulation
It's weird but true that as you read this your experience will be stored as a memory in meat. The human brain is squishy and easy to damage. Worst of all there's no easy way to back up the brain.
If the mind can be uploaded and rendered into a digital facsimile than a lot more things are possible. As this Isaac Arthur's video points out several times the efficiency would be limited by Landauer's principle. If you're willing to have the computer running an emulated conscious run slower in an environment with as little thermal temperature as possible the efficiency can be maximized.
Time for the digital conscious could be "frame-jacked" to perceive time at different rates. Days outside the simulation could pass as decades are centuries are experienced subjectively by the digital conscious. "Time is energy" as the video points out. Any number of different minds could be in simulations running at different speeds. Scenarios could be played out or reversed backward for examination. The awareness that what what is happening is a simulation could be taken away.
Hey, there's some weird déjà vu. I just looked away from my computer and saw the same black cat shiver and continue walking past a doorway the same way. Where did that cat even come from and where did it go? How strange. Maybe a ghost?