Nintendo Japan have uploaded a seven minute overview of the SNES Classic Mini which includes a look at the hardware, an extensive look at the UI and a first look at a new rewind feature that wasn’t present in the NES Classic Mini.
From what I can see, this feature will allow us to rewind in games. For instance, if you die in Mario, you’ll be able to rewind to just prior to your death and continue on.
There’s also a lovely run through of all of the games on the system as well as when they released. The brilliant touch is obviously fast forwarding all the way to 2017 where Nintendo highlight the release of Star Fox II.