In a scathing editorial in The Guardian, Epic Games cofounder Tim Sweeney spoke out about Microsoft's Universal Windows Platform (UWP) initiative, calling it a "fiasco" and "the most aggressive move Microsoft has ever made."

"With its new Universal Windows Platform (UWP) initiative, Microsoft has built a closed platform-within-a-platform into Windows 10, as the first apparent step towards locking down the consumer PC ecosystem," said Sweeney. "Microsoft has launched new PC Windows features exclusively in UWP and is effectively telling developers you can use these Windows features only if you submit to the control of our locked-down UWP ecosystem."

"PC UWP can, should, must, and will die as a result of industry backlash," Sweeney said.

UWP was launched as a way for developers to create applications that could run across several devices, including Windows 10-powered PCs, mobiles, tablets, and even Internet of Things devices. However, all UWP apps must be sold through the Windows Store where Microsoft takes a 30 percent cut. While not criticising the Windows Store itself—"I believe Microsoft has every right to operate a PC app store and to curate it how they choose," he said—Sweeney is accusing Microsoft of "unfairly disadvantaging" competing stores like Steam and Origin, as well as those who sell games directly to customers.

"The specific problem here is that Microsoft's shiny new 'Universal Windows Platform' is locked down, and by default it’s impossible to download UWP apps from the websites of publishers and developers, to install them, update them, and conduct commerce in them outside of the Windows Store," said Sweeney. "It's true that if you dig far enough into Microsoft's settings-burying UI, you can find a way to install these apps by enabling 'side-loading.' But in turning this off by default, Microsoft is unfairly disadvantaging the competition."

Sweeney then compared UWP to Google's Android, which is "technically open, but practically closed" thanks to how "comically difficult" it is for general users to sideload apps. "This is not merely a technical issue: it has the market impact of Google Play Store dominating over competing stores, despite not being very good," he says.

Even more damning is Sweeney's fear that as Microsoft continues to develop UWP, it may include features that don't make it across to the Win32 API used to make standard Windows desktop applications, including games. This would make it difficult for developers to not use UWP in the future, even if they're able to right now. Sweeney claims this has already happened with certain Windows features.

"Microsoft has launched new PC Windows features exclusively in UWP and is effectively telling developers you can use these Windows features only if you submit to the control of our locked-down UWP ecosystem. They’re curtailing users' freedom to install full-featured PC software and subverting the rights of developers and publishers to maintain a direct relationship with their customers."

Sweeney's comments follow a spate of backlash from consumers over the upcoming launch of the Microsoft-published game Quantum Break. In addition to only running under DirectX 12—thus making it exclusive to Windows 10—Quantum Break will only be available as a UWP application sold via the Windows Store. UWP apps are subject to a host of limitations, including not being able to turn off V-sync, (currently) no SLI or Crossfire support, no .exe file for use with Steam, and no custom mouse and keyboard bindings. Game files are also locked down, which prevents modding.

Microsoft's Phil Spencer later responded to those comments on Twitter, saying the company has "plans to improve."

Those plans, however, don't appear to have come soon enough for Sweeney. While the developer credits Microsoft with listening to Epic's concerns with UWP and hopes "Microsoft would do the right thing," it has so far failed to make any changes to UWP.

"[Microsoft is] working to turn today's open PC ecosystem into a closed, Microsoft-controlled distribution and commerce monopoly, over time, in a series of steps of which we’re seeing the very first," he said. "Gamers, developers, publishers simply cannot trust the PC UWP 'platform' so long as Microsoft gives evasive, ambiguous, and sneaky answers to questions about UWP’s future, as if it’s a PR issue. This isn’t a PR issue, it’s an existential issue for Microsoft, a first-class determinant of Microsoft's future role in the world."

Sweeney offered a solution to the problem, asking that Microsoft allow any Windows user to download and install a UWP app from the Internet, just like regular desktop apps. He also asked that Microsoft not restrict the use of other stores like Steam on Windows.

Unfortunately for Sweeney, Microsoft seems hell bent on making UWP the future of gaming on both the PC and the Xbox One. As we noted earlier this week, Microsoft's insistence on forcing these console-like restrictions onto the PC simply isn't going to fly with an audience and set of developers that value the freedom of the platform.

"Does Microsoft really think that independent PC developers and publishers, who cherish their freedom and their direct customer relationships, are going to sign up for this current UWP fiasco?" asks Sweeney.

Ironically, one of the few games available on the Windows Store is Epic's Gears of War: Ultimate Edition.