Yeah, this is the first game I have ever looked at the code to figure things out. And to be honest, even after looking at the code, I am almost certain that certain achievements are not possible and some endings are going to require that you make very specific choices and if you vary on more than one of those you won’t get the ending you desired. There is too little margin for error in decision making that isn’t always clear.
Edit: After many attempts, I can say with certainty that there are far too many achievements that are not attainable even looking at the code for every choice and way too much of the story that will never be seen unless you follow one exact path. If, and I highly doubt this, you have achieved 100% achievements, you should definitely make a guide. I would even pay more than the game’s cost for this because I don’t think it is possible and the guide would need to be nearly as detailed as the whole story.