The Half-Life: Alyx was made for the Valve index therefore it's really good to play it with the Valve index, and not to mention you get it for free when you buy the VR!
It runs at 60 fps and 144hz which is amazing for a VR, the Amazing and Lush graphics really make this game feel real.
the controls for the game are really good to very realistic and not too complicated anyone could control the game, the movement doesn't make you sick or wanna throw up and the headset is really comfortable too, but enough for the headset we are here to hear about the game.
Half-Life Alyx offers a really good story that keeps you wanting to play more of it, it's definitely worth 60 € there is about 15h of gameplay but you can download some workshop maps if you want a bit more of the gameplay
here is a picture of how the game looks:

Yes, this is actual gameplay, not a clip out of a trailer. The lighting in the game is also just amazing how the light leaks into the room really makes the game look good.
That's all that I have to say about the game it's simply amazing