Simply one of the most well rounded VR games out there that has left the realm of tech demo,
and proves to show what the VR medium can do when enough resources are invested into it.

From a mechanical perspective, there isn't anything here you haven't seen in other VR games before,
but probably never combined into one game and executed at such a level of polish.

And that is what makes Half-Life: Alyx special.

As far as it being a Half-Life game is concerned;
it is a worthy entry into the franchise that has some serious unforeseen consequences on the main story line.

If you already have a VR HMD: Get it.
If you don't but are into the Half-Life franchise: Get an Index and get this game for free (Some other HMDs also include it).
If neither fits your bill: Find someone who has it and at least give it a try.