Edit: As a side note, this is why I'm extremely skeptical of things like VR technology in general (as a person that owns a HTC Vive). I'm not sure we're going to be able to easily convince the human brain it's OK for different sensors to feel different things, and not result in us feeling sick.
That's why even though I'm a relatively avid gamer with plenty of disposable income, I've never bought on to the VR stuff. It's not about the cost, or the rapidly improving technology, it's that I don't believe (long term) that I'm going to really enjoy many VR games.
I have a racing wheel because I like to play racing games, but most of the time I end up using my controller anyway. Why? Because it doesn't feel real. The wheel ends up feeling farcical because yeah I'm cornering at 1.5G, but I don't feel a thing. In real life you're less likely to corner too fast because you can feel that you're going too fast. You're being shoved around, you're being moved side to side, you're sliding forward as you brake and backwards as you accelerate. In a video game you get none of that, and you become detached.
I think there will be plenty of valid VR experiences, once we figure out what's the right fit. Windows Mobile took the desktop and put it on a phone, it wasn't until Android and iOS came out that we figured that smartphones are really actually quite cool, provided you build the right interface. We now know there are just things you can't (or shouldn't) do on a mobile device compared to a desktop, and we build around that.
I don't know if playing an FPS in VR is ever going to feel "right" because you're entering the uncanny valley of "I'm walking up the stairs but I'm not actually". At least on Counter Strike you're just pushing buttons on a keyboard and looking at a small rectangle, so your brain knows it's not actually supposed to be happening.
It's like walking with pins and needles.
Even people with impressive visual hallucinations are still capable of walking.
That said, vertigo (where your eyes and your inner ear are in violent disagreement as to whether you are moving) can impair movement, though you can grow accustomed to the "disagreement".
The difficulty may be down to you trying to use other senses and overcompensating on the data (e.g. air pressure, which tells you something is near-ish you but not if it's about to contact you so you react)
Ideally all sensors would be redundant, with poorer and poorer (but still safe) performance as each is removed.