Twenty months after it started, Valve's experiment in letting developers sell unfinished games through its Steam Early Access program continues to evolve. Giant Bomb reports that the distribution service has sent a new set of rules and guidelines to Early Access developers about how they should market and position their games.

The most important new rule might be the requirement that developers clearly communicate a game's unfinished status wherever Steam keys are sold outside of Valve's storefront. As Valve notes, "We've seen that many of these titles are sold as keys on other websites where there is no explanation of what Early Access is or what the current state of your product is now versus what you hope to achieve." This extends to setting proper expectations for the project "everywhere you talk about your game," Valve says.

Early Access developers must also avoid "specific promises about future events," such as when a game will be finished or what features are planned for future updates. "Customers should be buying your game based on its current state, not on promises of a future that may or may not be realized," Valve writes.

Aside from those requirements, Valve also outlines some suggested guidelines born from experience watching Early Access projects stall or succeed over the past months. Developers in Early Access should be able to continue working on the game even if it doesn't sell well in its unfinished state, but also shouldn't offer a nearly complete game as "Early Access" just to get final bug testing done. Valve also recommends that Early Access games be in a playable state from the first day they're sold, and not just tech demos or a collection of concepts.

Valve's new focus on Early Access rules comes just days after the publication of an EEDAR analysis showing that well under half of all games on Steam Early Access ever advance to a full release. Back in June, Valve updated its early access FAQ to explicitly clarify that "some teams will be unable to 'finish' their game. So you should only buy an Early Access game if you are excited about playing it in its current state."