These are the main points of that correspond to the level of VR Motion sickness you will experience:

1. VR Headset Refresh Rate (90hz is ideal)
2. Computer Hardware
3. VR area setup
4. Game Settings
5. Locomotion choices

While you may not be in position to change the first two, you can make an impact on the last three points.

Look at the Performance guide for more details about game settings.
How is your VR station set up? Are you using standing floor or room scale?
If you are using standing floor or you are sitting while playing this game, in that case you may have a bad time. In lengthy experience of playing VR games, sitting or standing still while playing the game makes me sick.

Locomotion Choices
Use the default blink teleportation locomotion choice. This is based on my personal experience, all other modes caused me to get sick. You say you lose immersion, I say I'd rather not feel sick.

How do I know my game is performing well?
Your average Frametime (ms) needs to below or at what the headset's refresh rate.

How do I find that information out?
1. Confirm your VR headset refresh rate -Wiki Link to VR Hardware Specs[en.wikipedia.org].
2. Use Display performance Graph tool in the developer section of the Settings of Steam VR.
3. Load up the game while making sure the Display Performance Graph tool is turned on.
4. Play the Game and watch the graph


What am I looking for?
First, play the game. Run around look at stuff, shoot, and do anything that can spike the graph up. We are looking for any performance issues related to your GPU and rendering of the game.

How do I know if I'm having performance issues?
The graph will change colors from green to yellow, orange, red; Also spikes that go above the white line.

What is the white line and what do the colors mean?
The whiteline on the graph is headset's ideal frametime. Frametime corresponds to your refresh rate of your headset which corresponds to your framerate.

Example: Vive Pro
(For the sake of simplicity)
Ideal Performance: 11ms = 90HZ = 90FPS
Not Ideal: 16MS = 60HZ = 60FPS

If spikes go above the line, you are looking at high frame time which means your game performance will suffer.

Here are some really easy tips:
1. Make sure that all background programs are closed while running the game
2. Update your video card drivers. Seriously, it's made major improvements for me. If you don't know how, Google it.
3. Go to the Performance section of the game's settings. Lower your performance to Low.
4. Make sure that you have default settings for SteamVR Video section.

Steam automatically scales the resolution of your headset to match your GPU specs. I don't recommend manually setting this unless you know exactly what you are doing.

Half-Life Alyx is clearly resource intensive game. It's game engine is incredible as to what it could do compared to other games out the market. You may not have spikes in the quiet parts of the game, but you will certainly have massive spikes in frametime on the action sequences; The best parts of the game! Massive spikes in frametime means more opportunities of getting motion sickness.

I played the game the first time around on High settings and I felt okay for the first half of the game. It wasn't until we were nearing the end of the game that motion sickness got worse. The reason was because the end game has way more action sequences which means way more frame time spikes. I had to take days off from playing because of how bad my motion sickness was.

For the sake of my health, I'd rather play this game on the lowest settings to reduce the chances of motion sickness as much as possible. That goes for any other future VR game I may play.

Cheers!