Halo Infinite is the game of the year chosen by the audience of the Game Awards
Sometimes The Game Awards have nothing to do with logic, and here's an example that partially proves it. Before tonight's ceremony, which will award games of the critics' choice (and 10% of the audience's votes), a vote was held for the best game of the year chosen by the player/audience. And the victory was taken by a game that the players did not play for 24 hours.
Halo Infinite, which launched yesterday, is the game of the year chosen by the audience. Halo garnered more votes than the competition made up of Forza Horizon 5, Resident Evil Village, Metroid Dread, and It Takes Two. Interestingly, Halo Infinite did not win in the previous round of voting - It Takes Two had more votes then.
At the time the vote began, Halo Infinite was not fully available to players. The multiplayer component was there, but the campaign was not. Admittedly, nowhere was it indicated whether to vote for Halo Infinite multiplayer, the campaign, or Halo Infinite as a whole.
It is a bit contradictory in this whole situation that Halo Infinite could not be among the critics' award nominations, considering that only games that came out until November 19 were taken into account. Therefore, the best game of 2021 by the audience is the one that critics will be able to nominate only in 2022.