Epic Games Inc CEO and founder Tim Sweeney has leveled some harsh criticisms at Microsoft’s Universal Windows Platform (UWP), calling it “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,” Sweeney wrote in a recent op-ed for The Guardian.

He added, “Here, Microsoft is moving against the entire PC industry – including consumers (and gamers in particular), software developers such as Epic Games, publishers like EA and Activision, and distributors like Valve and Good Old Games.”

Sweeney explained he is not against the idea of Microsoft launching its own app store on Windows, but fundamentally rejects what he believes is Microsoft’s goal with UWP.

“My view is that bundling is a valuable practice that benefits users, and my criticism is limited to Microsoft structuring its operating system to advantage its own store while unfairly disadvantaging competing app stores, as well as developers and publishers who distribute games directly to their customers.”

“PC UWP can, should, must and will, die as a result of industry backlash”

In his article, Sweeney listed out a number of changes that he believes have to happen in order for UWP to survive.

These changes include allowing users to easily download UWP applications from anywhere on the web, allowing any company to operate its own Windows game and app store in UWP format, and allowing developers and publishers to sell UWP format programs without Microsoft taking a 30 percent cut.

“In my view, if Microsoft does not commit to opening PC UWP up in the manner described here, then PC UWP can, should, must and will, die as a result of industry backlash,” Sweeney 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.”

Xbox head Phil Spencer responds

After the release of Sweeney’s article, Xbox head Phil Spencer refuted the Epic CEO’s claims on Twitter.

Windows has always been an open ecosystem welcoming the contributions of hardware and software partners, and will always continue to be.

— Phil Spencer (@XboxP3) March 4, 2016

In another tweet, Spencer called UWP “a fully open ecosystem, available to every developer.”

He also added, however, that Microsoft would be revealing its next steps for UWP at its Build 2016 conference, which will take place from March 30 through April 1 in San Francisco, California.

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