With the full reveal expected this Friday. And sure, it may not be the Half-Life 3
that people are still strangely clinging to as a thing that will happen one day - Valve
are referring to Half-Life: Alyx
as a flagship VR game. Meaning that it's designed to be the potential killer-app that VR sorely needs.
Compared to say, the current crop of AAA-style games we've been getting in recent years - VR games are mostly casual experiences. Here's the Tweet from Valve (who also now have a Twitter account).
As per the title it's expected that the focus will shift away from Gordon Freeman towards Alyx Vance - the resistance fighter that became one of the key characters in Half-Life 2. With Valve releasing its own VR headset in the form of the Index (in addition to running the SteamVR platform) it makes sense that it would be working on VR titles to support the hardware.