Fan fiction can commence at any episode or moment. Some authors might pick a key scene from the source material and build on it, while others might create an entirely new starting point. It's all about the author's creativity and vision.
I'm not entirely sure as I haven't read it in detail. But generally, a visual novel often involves a story with characters, plot twists, and multiple endings. 'Rumbling Heart' might be about relationships, emotions, or personal growth of the characters in the story.
" Celebrating Years 2 " was the second work in the novel series, with a total of 200 episodes. The first 100 episodes were the first. Celebrating Years 2 started from the 101st episode.