I'm trying some ideas for multiples save games on the web version of Quest 5. I did some tests saving one or more "walkthroughs" in the browser local storage AND the game object. The load operation just plays theses moves using HandleCommand. The "official" save game contains all saves. In order to load a save game that is not the last, all saves are stored at the client, the game is restarted, and the games are transferred from the client to the server, where the player can choose what one he wants to "load".
In theory all works. In fact I did a small working example. My question if there is another easier way to do that.
One problem for this solution is the desktop version, that just don't have a full browser with local storage. However, the desktop already have the possibility for multiple saves :)