As long as players can continue to encounter meaningfully different game states, they will enjoy making decisions on the fly. If they decide that they have seen everything your game has to offer, this is the moment when it transforms from chess to tic-tac-toe.
Quotes about replayability
Games that focus on [the precariousness of historical events] have a ready answer to the issue of replay-value: players should want to replay the game multiple times to appreciate the subtlety of the contingent factors that lead to some historical event. And they can offer genuine engagement with the history. One can come to a deeper appreciation of the details of historical events by experiencing what happens when those events are slightly altered.