Read the story about Oculus (I think it’s called “The History of the Future”). I seem to recall older headsets cause sickness for many people because the refresh rate isn’t quick enough on the displays. Newer Oculus headsets address this apparently.

I used to get virtual narcosis (it’s a term from Wired magazine many years ago) bad. There used to be a VR game at the top of Stratosphere in LV many years ago. I played that game, took the headset off, and had the worse case of virtual narcosis in the rotunda. Not a good experience.