So the demo on itch is currently Chapters 1 and 2 only. All the chapters (8 total) will be in the full game release. If I'm assuming you are asking if the story will release all at once, the answer to that is also yes. Once you pay for the game you'll have access to the entire story as it will all be released day one. I hope I answered that right, feel free to correct me if I was mistaken on your question.