What is the requirement for any new games? Why is this so?

To be approved for people to play, any new game in the World State must have at least as much apparatus as the most complicated game already in existence. As the director explains:

imagine the folly of allowing people to play elaborate games which do nothing whatever to increase consumption. It’s madness. Nowadays the Controllers won’t approve of any new game unless it can be shown that it requires at least as much apparatus as the most complicated of existing games ...

There is actually a method behind this madness. Huxley wrote his book around the time of the Great Depression. One of the causes of the Depression was the over-supply of consumer goods. Factories had been making these goods--cars, clothing, furniture-- faster than people could consume them. Therefore, inventories piled up. When companies realized they had a backlog of product, they naturally stopped producing more, laying off workers. When workers were laid off, they had money worries and naturally cut back on consumption, leading to a cycle of even more layoffs until the entire economy had ground to a slowdown, leading to a stock market crash.
The director is therefore showing one of the ways the World State keeps consumption high and factories humming along, so that the economy stays robust. Keeping people superficially happy is the goal of the World State, so the leaders have to manage the economy to avoid any recessions or depressions.

In chapter 3, the Director shows the students several hundred naked children playing while twenty children patiently stand next to a chrome steel tower, which is an essential apparatus needed to play Centrifugal Bumble-puppy. As the children attempt to catch a ball that flies out of the apparatus, the Director mentions that in the past, games were played without complicated apparatuses and devices. He scoffs at the fact that games used to be played with simple sticks and balls and proceeds to say that in modern times, the Controllers will not approve of any game unless it increases consumption. In the World State, games are required to have complex, expensive apparatuses and devices that cost people money to play. Leisure activities have been monetized, and the citizens of the World State enjoy elaborate, complex, technologically advanced games like Obstacle Golf, Centrifugal Bumble-puppy, escalator squash, and Riemann-surface tennis. These games are expensive to buy and play, which benefits the World State's economy.