I was expecting this to happen, but perhaps not quite this quickly. It seems modder Vect0r had no intention of hanging around to play Alyx, though, as he's already brought out a demo of Half-Life 2 running within the game, less than a week after it;s release.

There's been other ways to try Half-Life 2 in VR, such as via Garry's Mod, and there's already a port in development on Steam Greenlight. This method seems like it might be more impressive and quicker to implement than both of these, however - porting the game to Half-Life: Alyx.

There's already a technical demo (above) to check out, a little under a week after Alyx launched. Apparently, converting maps and assets between Source and Source 2 isn't all that difficult to do.

Vect0r did state however that the SDK for Source 2 is currently limited, so this may prove to be a barrier further down the road. Still, the work achieved in less than one week is very, very impressive.