But I don't think just adding "?game=backwards" would work you need Id of previous chapter
Yes... the code says the same ^^ (it checks if the id is the same as the previous id in the save game)
But is there any way my original suggestion works, you know if the chapter is not deleted but next chapter has a condition involving a new variable so when you start game, Chyoa checks for changes in previous chapters and if there is a new variable calculates the new score which results in next chapter being available. You could even ask readers if they want to perform this check or not 'cause I think it will take some time to load a saved game if site has to perform a check like this.
Well, this sounds rather complicated.
With formulas, it would be possible to provide a default value if a variable hasn't been set before, so that might solve that problem.
As the owner of a game story, you could also add versioning to your game. If the chapter requires a higher version, you could inform the reader at the beginning of the chapter.
So you would start with a variable "version" that is set to "1" in the introduction.
In every following chapter, you would use
Code:
{if version < 1}[Notice: "Please reset your game" ... *offer link*]{endif}
(You would need an additional statement if the variable version doesn't exist yet.)
Now if you add something quite early, you would change the variable version in the introduction to "2".
Additionally, you would need to change all (key) chapters after the introduction of the new variable to "< 2".
If a user still has a game with 1, they will see the note.
Alternatively, you could use the version at key chapters to actually fix the save game.
So if the version is too low, you would block all other options and offer an option "update savegame to version 2". This link (condition "version = 1") would then add the missing variable with a default value to the save game and sets the variable version to 2. Then it redirects back to the mentioned key chapter. If there is still another version, you could do the same again until the savegame has been updated.