Bonjour Claude!
Its not quite a miracle, but to get this to reset should be quite straightforward.
How I would do it, is firstly, set your MENU slide properties to "Reset to Initial State" When Revisiting
Then set up a simple T/F variable for each mission.
At the start, set all 3 variables to FALSE.
When the user gets the mission correct, set the variable to TRUE.
Finally, add a trigger to the MENU slide which says
Change state of MISSION1 BUTTON to State "Completed" when Timeline Starts on This Slide
And if you copy that same trigger for MIssion 2 and 7 buttons then this should work great.
The slide will show if the missions are complete, but if not, then the button will stay shown in the "Normal" state.
Does this help at all?