There will come a time when games making their way to the Oculus Rift will be so commonplace that it will not be newsworthy. Today is not that day. Especially not when the game in question is Half-Life 2.
The mod itself, like the Team Fortress one, is official but according to Valve programmer Joe Ludwig, it's not quite as polished. I don't know how long you'll be able to handle watching the above vid — I always struggle because I feel like no real perspective is provided. What is the person playing doing? Most of these vids just feature commentary alongside video of the Rift's two screens, the video signal that's actually being transmitted to the Rift itself. It doesn't really give anyone a real sense of what it's like to be in that world.
Still, thought it might be worth watching, especially for fans of Half-Life 2. More than anything it's just reassuring to see how much support Valve is providing for the Rift. I really, really hope this thing cracks the mainstream, because it's truly incredible.