After five years of work and its own period of "development hell", the long-anticipated Half-Life 2: VR mod will finally enter public beta this September. Created by a group called the Source VR Mod Team, it's a VR implementation of Half-Life 2 in the style of Half-Life: Alyx, letting you go toe-to-toe with the masked thugs of an alien police state as if you were really there. Good luck with those incredibly long vehicle sections, motion sickness sufferers.
The nature of a trailer is that you're only going to see the choicest cuts, but it looks surprisingly good for a project that was once "all but abandoned", in the team's own words. If I didn't know better, I'd say I was looking at an official VR version of the Valve classic. Maybe it's smoke and mirrors, but the modders say that they were inspired to enter public beta by the "overwhelmingly positive" feedback they got in private testing, which convinced them the game was finally playable "from start to finish" in its VR-ified version.
The mod will be free of charge, and playable by anyone with a copy of Half-Life 2 and a SteamVR-compatible headset. The creators say it's been successfully tested on the Valve Index, Oculus Quest, HTC Vive, and Pimax VR headsets, but it should be good to go on anything you can run SteamVR on. They're still waiting for approval from Valve to release on Steam, though, so you might have to use a standalone installer if you're desperate to play it as soon as possible.
The biggest caveat is that you aren't going to be able to run this thing on a standalone headset; you'll need to be hooked up to a PC to play it. The Oculus Quest 2 is, theoretically, powerful enough to run the mod, but the absence of an Android port of the Source engine means that there's no legal way to do so.
The creators say that no project like this is "ever truly finished", and this is only a public beta, but they do have plans to eventually bring Half-Life 2 Episodes 1 & 2 to VR as well. Once there's a public release of HL2: VR and initial bug reports have been dealt with, they plan to "slowly move our attention to the episodes" and bring them to a set of goggles near you. Personally, I think having two hands might neuter the most important challenge of the 2nd episode: ferrying Gnome Chompski from one end of the game to the other, but I suppose that's why I'm not a hotshot VR modder.