Update: It looks like Microsoft has in fact restricted the free game to a list of 25 titles that are available to choose from when the buyer adds the console to the Microsoft Store cart.
Original story: Microsoft has already cut the price of its Xbox One console bundles by $50 from now until December 26, but now the Microsoft Store site has a special one-day offer that makes it an even better value. The site is letting people get an extra free game of their choice when they purchase the console.
Just to be clear, this offer is on top of the free copy of Assassin's Creed Unity that the Microsoft Store site already offers for any Xbox One console, plus any game that's already bundled with the Xbox One. The game can be priced up to $59.99. This one-day offer is also available for people who buy the console at Microsoft's physical store locations.