Hey, I appreciate the feedback. That being said I'm a little uncertain about what it is you're asking for, as the phrasing "add in a save function" makes it sound like the game doesn't already have multiple ways to save.
I ASSUME you're suggesting I add an option to the pause screen so forgive me if I'm just totally misunderstanding. But assuming that was what you meant I will not be adding that as a feature to any build. The game was just never built with the idea of saving anywhere in mind and several features and mechanics would be completely undermined if I were to include that.
As for the cutscene breaking your game that you mentioned, that's definitely just a bug caused by my oversight and I'm glad you mentioned it. I'll be sure to fix it for the future.
However I'd like to mention that there aren't likely to be more demo updates from here on. With the games first two chapters now included there simply is no more content left to be squeezed out of the early sections so you shouldn't have to worry about restarting or losing any progress for a good long while.