It all started with these stark words from Gabe Newell of the gaming company Valve: “Windows 8 is a catastrophe for everyone in the PC space.”

Newell, who has emerged as a voice for openness in the realm of gaming, was speaking at the Casual Connect game conference in Seattle (and his words were reported by the BBC and others). It’s Newell’s belief that the success of Valve, which incidentally has produced the greatest video game of all time, is largely due to the open nature of PCs and the internet. We’ve been a free rider, and we’ve been able to benefit from everything that went into PCs and the internet,” he reportedly said. “And we have to continue to figure out how there will be open platforms.”

Newell’s concern appears to go something like this. Mobile platforms, and especially iOS, have been wildly successful. Windows 8, with its iOS-y “Metro” interface and its reliance on a Windows Store within the OS, is imitating iOS and its lucrative but limiting “walled garden.” This may be good for Microsoft, but arguably bad for gamers and game designers, who thrive on the creativity enabled by an open platform. “There’s a strong temptation to close the platform,” Newell reportedly said, “because they look at what they can accomplish when they limit the competitors’ access to the platform, and they say, ‘That’s really exciting.’”

(It should be noted, of course, that Newell has a financial stake in all this, since Valve’s Steam platform is arguably a competitor of the looming Windows Store, as Ars Technica points out.)

This week, other game designers chimed in and piled on Newell’s criticisms, according to TheNextWeb. “If Microsoft manage to close Windows and get to the point where every app has to be approved and certified by them, it’s game over for a lot of indies including Introversion,” said the creative director of Introversion Software on a Reddit thread. Rob Pardo of Blizzard Entertainment likewise tweeted that Windows 8 would be “not awesome for Blizzard either.”

Meanwhile, Newell has reportedly expressed an interest in getting into hardware manufacturing himself, should it come to that (see “Is Valve Making a Console?”)

Not everyone agrees with Newell. On a lengthy comment thread over at TheNextWeb, a man named Martin Walsh–a former head of marketing for Microsoft, it should be noted–called Newell’s comments “the dumbest.” (Newell is also an ex-Softie, interestingly). Walsh claims that platforms like Steam can still distribute games through Windows 8, and he contests the idea that a “full-blown game” is likely to be purchased through an app store. Walsh sees the expanded reach of the Windows Store as nothing but a blessing for game designers. Other commenters on the site disagree with Walsh.

It’s difficult to pronounce on this, of course, until we actually see Windows 8, the Windows Store, and how gamers and game makers interact with the platform. One thing’s for sure, though: Newell has been one of the most influential and innovative figures in the history of video games, and if he’s worried, I’m worried.