The head of Valve Software, the company behind the Steam platform, has called Windows 8 a “catastrophe” for the PC games market.

Gabe Newell predicted that Microsoft’s changes with the new system could be a major deterrent for games manufacturers. He warned that Windows could become far less open and in turn would stifle innovation.

Newell didn’t go into extensive detail, but his main concern appears to be the prospect of PC owners who run the default Metro setting in Windows 8 sticking only to the official Microsoft app store, rather than going to the effort of switching to the more traditional desktop display and installing software manually.

Valve, which distributes its own games directly though Steam, won’t be enthralled about the prospect of having to either agree to Microsoft getting a cut of its revenue, or missing out on potential sales. It’s also worried that games makers may be tempted to stick to the Microsoft store and miss out Steam altogether.

Newell also admitted that Valve’s recent efforts to bring Steam to Linux are a “hedging strategy” in case it does indeed see a drop in Windows business.

After noting that many online firms were only able to develop their services because the PC as a whole is a relatively open platform, Newell said of Microsoft that ” I think there’s a strong temptation to close the platform. If people look at what they can accomplish when they can limit competitors’ access to their platform, they say, ‘Wow, that’s really exciting.’… That’s not how we got here, and I don’t think that’s a very attractive future.”

And it’s not just gaming where Newell thinks there’ll be problems. He outright says that “I think that Windows 8 is kind of a catastrophe for everybody in the PC space. I think that we’re going to lose some of the top-tier PC [original equipment manufacturers]. They’ll exit the market. I think margins are going to be destroyed for a bunch of people. ”

(Image credit: Game Developers Choice Awards)