In a Reddit AMA, Valve’s Gabe Newell confirmed that his company is working on unannounced games and that a Half-Life related title isn’t out of the question.

　　As could be expected from the Valve founder, Newell didn’t confirm development on Half-Life 3 but did state that his company is working on at least one “fully-fledged” single-player title. "The number 3 must not be said”, Newell replied when asked about Half-Life 3.

　　Gabe Newell, as always, remained tight-lipped about a possible Half-Life 3 and Valve’s upcoming titles. "I personally believe all unidentified anonymous sources on the Internet”, he said when asked about an unidentified anonymous source that claimed the cancellation of Half-Life 3. However, he did give a little bit of hope that perhaps a new IP set in the same universe of Half-Life could arise at some point.

　　Other than confirming that the unannounced games mentioned above, will run on Valve’s Source 2 engine, Newell remained vague.

　　“We are continuing to use Source 2 as our primary game development environment. Aside from moving Dota 2 to the engine recently, we are using it as the foundation of some unannounced products”, he said during his AMA. “We would like to have everyone working on games here at Valve to eventually be using the same engine. We also intend to continue to make the Source 2 engine work available to the broad developer community as we go, and to make it available free of charge.”

　　The exact nature of Valve’s upcoming new projects is uncertain, but at least we can expect at least one single-player title, whether this is related to the Half-Life franchise remains to be seen, but it hasn’t been totally ruled out. We'll keep you updated whenever the studio choose to reveal more, of course.