We are currently looking into that.
Yesterday, I just added one little variable and all saves broke. (KeyError main_menu_screen)
But not because of the variable, something else is causing this.
We suspect it is because I am on a Renpy version that was used during WW2 (7.2.2) and I am currently porting the game to 7.3.5 and see if that helps.
If not, I will have to get in contact with some Renpy-masters.
I think I wrote Chapter 3 while being sleep-deprived. I then tend to do a lot of little mistakes. But it's been like 1- 1 1/2 years since I wrote that Chapter and my engrish got a little better.
And I got in contact with a professional proof-reader and he is currently proofreading the entire game.
The full version won't look like some cavemen fell on the keyboard.
I also fixed most of the code already but thank you for pointing them out!
P.S: I like his hair