It doesn't matter if you're the butt of the universe, Amagidyne, the older sister of that woman, confused about your feelings, Brojima, Deredere, meatloving kicker, cousin, money-grubbing fox, the detective that can be shipped to at least 3 people, those two guys, the depressing guy, the old lady that "personifies death", the average-looking mom, the hot nurse, the insufferable kid, the bear, the tsun whose links gets progressively better, the forehead and apple cheeks, etc. Being associated with the MC is enough to be in his harem.
Well, the "Kings Game" scene was in the game. In the game, you could choose to have someone sit on your lap, rest their head on your lap, hug you, or something else (a piggyback ride, I think). But you only got to choose one.
In the anime, they did all of them, kind of like this. Right down to the "I don't care at all" look on Yuu's face and pose. And Yousuke getting jealous.