Does anyone know how to modify the save files of this game?
Yeah, but . . . be careful where you poke around. Always keep your original just to insure things don't blow up.
I'll start at where to find it for posterity's sake.
1) Go to Users/[UserName]/AppData/LocalLow/TeamApplePie/Save
2) Select the .Sav file you want to modify.
3) Choose an online editor of your choice (saveeditonline.com and saveeditor.online are both applicable)
4) Root through hundreds of values with barely any information on who links to what.
No seriously, even fresh saves have way more characters listed than exist. Make sure you aren't modifying an enemy or your doors without knowing.
4ex) m_CharacterList > 3 > m_Health 25 m_CharacterList > 3 > m_MaxHealth 25
Change to m_CharacterList > 3 > m_Health 1025 m_CharacterList > 3 > m_MaxHealth 1025
That would only change the Max Health (and Health, obviously) of that unit, no passing down.
Now if you did m_CharacterList > 3 > m_Health 1025 m_CharacterList > 3 > m_MaxHealth 1025 m_CharacterList > 3 > m_Health_Additional 1000, you should be able to pass on that 1000+ health from base.
Now, the character list should be populated based on order created, but I'm not going to guarantee it won't get weird overtime. Doors are also characters.
I'm also not claiming this is the best explanation, since I'd rather just inject small scripts to do things like modifying base files (or modifying the files directly) to add things like areas to capture Nuns and buffing that. But it is an option.