The speculation mill has been running hot over the last few months. G-Man's voice actor Mike Shapiro rang in the new year by in which he refers to "unexpected surprises" in the staggering voice of Half-Life's dimension-hopping villain. Before that, evidence that Valve was working on a was revealed on an actor's website—White Sands referring to an area of New Mexico where Black Mesa was supposedly situated.
Now, Reddit user Relevant_Basis5444 has that Valve's Steam page currently lists two projects beneath its "Upcoming Releases" tag (via ). One of these is, Valve's third-person MOBA, which is currently in development, and technically unreleased despite of people playing it right now. The other, however, is hidden from view. It's worth noting that Steam developer pages can hide games from view depending on your filter settings. But this mystery game remains obscured even with all filters disabled.
Primed to view any unusual behaviour by Valve as evidence of Half-Life 3's development, fans have naturally speculated that this hidden game is Gordon Freeman's long-awaited third adventure. But it's worth bearing in mind [[link]] that it could really be anything, as the comments to Relevant_Basis' original post deliberate. Several users suggest this purported additional game is the result of a good old-fashioned bug, while others note this second title could be In the Valley of the Gods—Campo Santo's follow-up to Firewatch in development before the studio was acquired by Valve. However, Campo Santo has its own [[link]] Steam page where In the Valley of the Gods [[link]] is listed as an upcoming game, so it's unlikely to be that.