Moon and another attributes of the real Earth. Why?

[Xyno]

Another planet with the same colored seas, same air composition, same types of trees, many of the same/similar animals, and humans just like us. All of that stuff that surrounds us every moment of play and is astoundingly similar to real life, that's minor. But only one circle in the sky, that's major. That's gamebreaking and totally ruins my immersion.

As one man sad here, it is not a sci-fi. The world must have many similar things not to be frightened, to be comfort