Rewind will vary depending on what game you're playing. For example, the feature will allow you to go back as much as a few minutes in role-playing games like Super Mario RPG: Legend of the Seven Stars, but the time will be limited to around 40 seconds in action games like Super Mario World, according to Nintendo. The console will also sport the same "Suspend Points" save function that came on the NES Classic Edition. A teaser trailer (shown above) gives a brief glimpse of what rewinding will look like.
While the ability to rewind will almost certainly make games easier, it sadly won't help with getting your hands on an SNES Classic, of course. As of Tuesday afternoon, pre-orders for the $80 system appeared to be sell out at most retailers, if not across the board, in just minutes. For what it's worth, Nintendo has already promised more stock available on launch day, saying, "a significant amount of additional systems will be shipped to stores for launch day, and throughout the balance of the calendar year." See you in line on launch day.