Half-Life: Alyx's modding scene is surprisingly vibrant considering the relatively small number of VR headsets in the wild. Ongoing projects range from the impressive Half-Life Alyx: Levitation, to a mod that transposes Alyx's VR gunplay into Bioshock's Rapture. But those are all still heavily in development. Half-Life: Incursion, on the other hand, you can play right now.
Incursion is a "wave-based experience" that's designed to test your VR shooting skills against a small army of City 17's combine soldiers. "We felt the campaign was a bit lacking in challenge as it is very friendly to new VR users," say the devs on the mod's Steam Workshop page. "Consequently, this is a challenging level for experienced Half-Life: Alyx players."
The mod sees Alyx Vance become trapped at a combine checkpoint on the wrong side of City 17's Quarantine Zone. She must "manage her resources and use clever tactics" to survive the ensuing fight. Those aren't idle words, either. Incursion is designed to be more of a sandbox experience than the official campaign. The mod takes place in a large, open-ended level where both enemies and resources spawn in semi-random locations, meaning the experience will be slightly different each time you play. Some of these resources, like resin, can be brought to a Combine fabricator to craft a wide-array of weapons and weapon attachments. This includes a new weapon in the form of Half-Life 1-style trip mines.
The trailer above makes Incursion look like pretty intense stuff, with lots of opportunities for improvisational combat tactics. It's also worth noting the mod has its own bespoke voice acting for Russell, which is fairly decent, although he sounds less like Flight of the Conchords' Rhys Darby and more like a football commentator.
In any case, you can give Incursion a whirl by downloading it here. Installation is all done via the Steam workshop, so it should be fairly straightforward. If you don't own a VR headset, fear-not, there's plenty of other custom Half-Life action in the works, including a Ravenholm mod, a fan-made Opposing Force sequel, and a massive campaign where you play as a Combine soldier.