Unlike Xbox Live Arcade or Xbox Live Indie Games, "Games on Demand" allows players to buy full retail games directly on their Xbox 360. However, downloadable games typically appear weeks and months after their boxed counterparts. For example, the most recent batch of titles include Risen 2, Dance Central 3, and PES 2013--games that are at least five months old.

Games on Demand senior business manager Erik Yeager said that the delay is due to a "strong partnership" with retail.

"They're the ones out there selling the consoles, selling the peripherals and, in this time, we're trying to figure out how to fit that in to the whole digital landscape shift. We're just taking a bit of a measured pace with it," Yeager said at a recent MIT Business in Games conference (via Joystiq).

While pointing out the Games on Demand has been getting better with games being available on release day, he stressed that the partnerships are important because the retailers sell the company's console. "The ability to sell our console is the most critical thing for us. If you don't sell the console, you can't sell anything else."

However, Yeager's explanation makes little sense when looking at Xbox's rivals. Both PlayStation Store and Nintendo's eShop offer day-one downloads of retail games, both first and third-party. And last time we checked, Sony and Nintendo consoles are still sold in retail stores.