Sister Princess
There are two different endings for each sister: the normal ending and the "non-blood relation" ending. As the name would suggest, the special ending reveals that the brother-character and sister are not actually related by blood. In the case of some of the older sisters, this can lead to the protagonist and "sister" marrying one another. In the original "Sister Princess", the player can see two different endings for each sister, but "Sister Princess 2" has four endings for each sister. The first two were the non-sibling relation and siblings-together ending and, if the player chooses one sister in the beginning but ends up with another sister, either of the other two endings for the first sister who the player does not choose appear ("non-blood relation" ending and "still brother and sister forever" ending also) but with a different story.