I started playing Half-Life: Alyx tonight (err, I guess technically it would be "last night," seeing as it's after midnight and such.
I'm about 90 minutes into it right now and…goddamn. It's absolutely fantastic so far. One of my favorite moments so far has to be smacking a headcrab out of the air in mid-jump and putting about four pistol rounds into it while it's stunned. I was a little disappointed that I couldn't seem to beat headcrab zombies with a metal pipe, though. Might be a heavy-handed way of ensuring that HL:A doesn't end up becoming trivial due to "epic VR combat" (that is, waggling a melee weapon and causing it to rapidly deal damage to any target in front of you). Kind of a shame.
The pick-up system is a hell of a lot of fun, and (being able to bash head-crabs out of the way aside) is probably one of the most innovative parts of HL:A. Many VR games allow you to remotely grab an item. Generally this just involves pointing to it, looking for a highlight, pressing on the grip button, and having the item magic itself over to you in a straight line. HL:A, continuing with the trend set by HL2, makes use of gravity. Alyx gets gravity gloves very early on in the experience. To use them to grab an item across a wide gap, you gesture toward the item with an open hand, and when you see the highlight you hit the grip and flick your wrist. The item then flies toward you, with its speed and angle largely dependent on how hard/fast you flick. When it comes near you, you simply catch it. It didn't take long at all for me to get used to how much force I needed to use to get an item to me. I'm sure the catch radius is probably pretty generous, but it also feels like it's easier and more intuitive to catch objects than it is in many VR titles.
I haven't done much in the way of gunplay, and I currently only have the pistol, but so far I like how it's implemented. Weapon handling is actually done fairly realistically. Ejecting an empty mag will cause you to lose the rounds in the dropped mag, and if you empty the mag and then fire the chambered bullet you'll have to rack the slide after changing mags. About the only gripe I have is with Alyx's trigger discipline. Some games (like Gun Club VR) check the capacitive trigger sensor and will show the character holding their finger outside of the trigger guard. In HL:A, Alyx's finger is always in the trigger guard. Yes, this is a petty gripe, but as an experienced shooter it does drive me a little nuts.

This may not be an issue on the Index's finger-tracked controllers, but I dunno (I'm on a Rift S).
As with any other VR title, it's awesome seeing everything in its proper scale. It's really easy to underestimate just how big headcrabs are until you've seen one up close and personal (and thankfully not in person. Yeech) and actually fighting the jumpy little bastards is another thing entirely. I've only dealt with two so far (and about a dozen headcrab zombies) so I have a feeling things are only going to get more frantic.
Finally: visuals. HL:A is fucking
gorgeous. Easily the best VR visuals I've seen to date, by a pretty healthy margin, and despite that the game runs at a consistent 80hz on my system. It's not just that Source 2 is a shiny, modern engine, but Valve really pulled out the stops when it comes to overall detail. Striders climb up buildings, smashing terracotta roof tiles and sending dust and persistent debris all over the place. The buildings look lived in, with the cities being crammed with detail and evidence of decay, with the Eastern European vibe getting ramped up dramatically with plenty of pre-war Cyrillic leaflets and other materials in plain sight. It doesn't show off a large amount of the starting city, but the parts that it does show off are rich and dense, with an incredible attention to detail.
In terms of accessibility, the game does offer a variety of movement options, and seems to do its best to cater to everyone. Multiple movement options, a way of playing the game with a single controller, options to make seated play easier, subtitles, etc. I'm personally using controller tracked free locomotion, with 30° snap turning (I'm physically okay with smooth turning, but it's almost always too damn slow in action games). The game has several comfort features baked in as well. If it requires you to drop down a ledge, the action is smooth and slow, rather than subjecting you to the full fury of gravity. It also tends to avoid nudging the player back if they start to intersect with the scenery, allowing you to look behind objects without getting nudged all over the place against your will.
Whew. In case it wasn't obvious, I can't wait to play more of this thing. Valve really knocked it out of the park, and I hope they get back to making full-scale AAA titles instead of…Artifact. :|