For years now, Valve has struggled with the problem of what it should and shouldn't sell on the Steam store. At first, Valve was the gatekeeper. Then it introduced Greenlight, allowing Steam users to vote for games they want to see on Steam. Finally, it did away with all of that, and now allows anyone to put just about any game on Steam if they pay a $100 fee.

That's caused a couple problems for Valve, as the open process has led to Steam listing certain objectionable games that it later removed—despite its hands-off policy, Valve does have limits to what it'll distribute, at least when there's widespread criticism.

Right now, Epic is much like Steam was in the early days, negotiating Epic Store releases game-by-game, but it plans to open up the store more widely in the future. When it does, it won't take Valve's hands-off approach.

Earlier this week, I asked Epic CEO Tim Sweeney how Epic will decide what does and doesn't get to be published on the Epic Store. He began by explaining that the Unreal Engine side of Epic and the publishing side of Epic have "very different policies."

"The side of Epic that makes creative tools like the Unreal Engine available to everybody says that you can use our tools for creating anything that's legal, and we have no creative say in it—we can't veto, whether we find it controversial or tasteful or not," he said. "That applies to the Unreal Engine, because we see it like Microsoft Word. How insane would it be if Microsoft Word's EULA said 'you cant write this set of ideas in our word processing software?' We don't go there."

When it comes to what Epic itself puts into the world via the Epic Games Store, however, Sweeney said that Epic will apply quality standards "similar to what a movie theater might apply as to what movies they show."

"We'll have a quality standard that doesn't accept crappy games," he said. "We'll accept reasonably good quality games, of any scale, whether small indie games to huge triple-A games, and we'll take everything up to, like, an R-rated movie or an M-rated game. A GTA game would be fine to us, but Epic's not going to distribute porn games or bloatware or asset flips, or any sort of thing that's meant to shock players. The PC's an open platform and if we don't distribute it in our store you can still reach consumers directly."

A "quality standard" implies, to me, that Epic will play every game that comes its way before approving it, which would be a gargantuan task. That's not the plan, though.

"We're not going to have something like the console certification process involved in releasing a game," said Sweeney when I asked how Epic would apply this quality standard. "But I think we'll be aware of the quality of what's submitted prior to making a decision to list it in the store—somehow."

"Humans can make those judgment calls, and they'll be pretty reasonable," he added.

It's no big surprise that Epic won't be distributing porn on the same platform as Fortnite. Valve and Epic are similar in many ways—both are privately-owned companies that have massively influenced PC gaming in part by producing game engines—but Epic has always had a more mainstream persona. Valve is to enigmatic forum posts what Epic is to carefully-crafted press releases, and that difference is easily illustrated by imagining what would happen if an adult game released on the Epic Store right now, sat next to Fortnite. It'd probably be a global PR disaster, whereas Steam hasn't caused any widespread, mainstream stir by hosting adult games (except when those games are dedicated to crossing lines, as recently happened).

But beyond adult games, Epic refusing games on the basis of quality is another major way it's differentiating itself from Steam.

Despite their similarities, the two companies are displaying very different philosophies regarding game distribution. Epic has also argued that the 12 percent revenue cut it takes from games sold on the Epic Store is fairer than Steam's 30 percent cut. During our talk, Sweeney told me that Epic's 12 percent rate will not change, and that it can make plenty of profit under the model.