The gaming market is a market where the biggest companies barely have slighty above 10% of market share so there aren't monopoly issues. It also have many different submarkets.
The supposed worry with this acquisition is that in one of these submarkets, the one in the last position of the console hardware race would negatively affect the market leader of the consoler hardware race because wants to acquire a company that generates around 10% of the game sales for that market leader console, and if the case they make a game series console exclusive, something that according to market numbers and the acquirer research, wouldn't be profitable and wouldn't helpt them significatively grow in the market, because only a small portion of that around 10% of the market leader console would leave to the last one which has like half of its market share.
In an open market the acquisition would be allowed because doesn't significatively lessen the competition and doesn't create or helps to create a monopoly. Because even after the acquisition the company will have only slighly above around 10% of market share and will continue being the last one in the console race.