I think you are playing the Android version, some people have reported crashes in this version.
This problem is caused by the minimum requirements for mobile phones, apparently this game is not very optimized for mobile phones!
The game over screen appears every time the character starves to death or when the camp runs out of food! Remember that the main theme of the game is survival, so you need to eat and store resources at the camp.
Regarding the continuation of the story, there is a small event guide within the game, where you can find the locations and times when the main events of the story appear!
Regarding the files that rewrite the save, this problem is new to me. I'll take a look and if I find any bugs, I'll fix them in the next update!