Epic Games co-founder Tim Sweeney has railed against Microsoft, strongly criticizing the company's Universal Windows Platform, saying the tech giant is moving to lock down the PC ecosystem.

As co-founder of Unreal Engine house Epic, Sweeney is head of one of Microsoft's most prominent partners in the video game industry, giving his public criticism of Microsoft that much more weight. 

According to Sweeney, writing in The Guardian, Microsoft is trying to lock down the consumer PC ecosystem by building a "closed platform-within-a-platform into Windows 10."

Expressing his anger at Microsoft's decision to use the Universal Windows Platform (UWP), which allows devs to create apps that run on any Windows 10 device - be it a PC, Xbox, tablet, or smartphone - Sweeney told developers they must fight the move, or "cede control of their titles."

"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," wrote the Gears of War developer.

"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."

The problem, he says, isn't that Microsoft is trying to build out its Windows Store, but rather that its Universal Windows Platform is locked down - meaning it'll be impossible for consumers to download UWP apps, or install and update them without first going through the Windows Store. 

Sweeney also fears that the closed nature of the UWP means developers won't be able to distribute any games written using the platform without first receiving Microsoft's permission. 

In the long-term, that could result in Microsoft controlling the sale of PC games and Universal Windows Apps, giving them the ability to hold devs to ransom and ensure UWP releases are only available on the Windows Store. 

While Sweeney sees the UWP as a "walled garden", Microsoft has countered by explaining the platform is a "fully open ecosystem, available to every developer, that can be supported by any store."

Microsoft says it continues to make improvements for developers, and is only trying to make "Windows the best development platform, regardless of technologies use."

Speaking at a media event in San Francisco last week, Xbox chief Phil Spencer revealed the company was planning to build out a "complete gaming ecosystem for Universal Windows Applications."

For the full story head on over to The Guardian.