From the introduction:
Time travel is fantasy, rewinding is even more so. Not only does the player’s character travel backwards in time, they somehow retain their memories. It’s a mystery to be solved, but probably not with science. That doesn't mean that there are no rules. Rewinding usually has a triggering event and may have several; death, sleep, a fixed amount of time, or an at-will ability to rewind.
The game is designed for solitaire play, though a provision is made for two-player use (one player and one game master).