In a press statement by Nintendo, a new update for the Nintendo Switch Online NES Library will add two classic titles, Donkey Kong 3 and Wrecking Crew. But the part that has people's attention is a new rewind feature.
"A Rewind feature will be available to use with the entire collection of NES Nintendo Switch Online games, allowing players to easily rewind gameplay by pressing and holding ZL + ZR if they make a mistake or just want to retry a section of the game!"
Given the easy-to-fail nature of NES games, this would be a fantastic feature for people wanting to experience a game without worrying about save states or starting over.
The NES Library is a collection of classic Nintendo Entertainment System games from the '80s ported onto the Switch digitally. They are available as part of Nintendo's recent paid online service, Nintendo Switch Online. The service provides access to online functionality in any Switch game, cloud saves, and said NES Library. Every so often, Nintendo will expand the library's selection of games.