While some of Microsoft's older game titles, such as Age of Empires II HD (a 2013 update of a 1999 game) are found on Valve's Steam platform, its latest high-profile titles, such as Forza 6 Apex and Quantum Break, are exclusive to the Windows Store. But this is going to change, with Microsoft planning to release more titles on the popular store.

Phil Spencer, head of the Xbox team at Microsoft, was talking on Giant Bomb's E3 stream, via GameSpot. When it comes to PC gaming, the Windows Store is very much an also-ran, with Steam the dominant force. As Spencer noted, "I don't think Valve's hurt by not having [Microsoft's] first-party games in their store right now. They're doing incredibly well." Accordingly, Spencer said that Microsoft "will ship games on Steam again."

Meanwhile, Microsoft's own experience had been more inconsistent. While some games have done well in the Windows Store, with Spencer naming both Forza 6 Apex and Killer Instinct as successful titles, he said that "Quantum Break wasn't our best PC release" and that Gears of War Ultimate Edition was merely "OK."

The Windows Store is used to selling games built using the Universal Windows Platform. These have come under fire for certain technical restrictions that they suffer, such as having no option to disable V-sync and limited support for multiple GPUs. Microsoft is continuing to work to lift these restrictions: the Windows 10 Anniversary Update will allow disabling v-sync and will improve multiple GPU support, and the latest builds of Store app make it easier to install games onto different disks. This was a particular annoyance for large games such as the 50GB or so of Quantum Break—with many gamers preferring a fast SSD system drive combined with a larger spinning disk for their games, the Store's default to using the system drive for all installations was a problem.

Spencer did not say which games would be sold on Steam, nor when they would appear. Selling games this way could do more than merely open them up to a wider audience; it may also be useful in proving that UWP apps are not inextricably tied to the Windows Store and that they can in fact be sold by third parties. This has been a point of contention after game developer Tim Sweeney said that UWP is a "closed platform-within-a-platform" that "should, must, and will die," even though this isn't actually true.

Selling UWPs on Steam would underscore this point and demonstrate that third-party storefronts are perfectly possible.