> Been reading that motion sickness is mostly due to looking around an environment
> without moving your head at the same time (meaning you should keep eyes forward only
> and move head).
> That would explain why I felt sick after the Samsung demo, looking around at all the
> marvel characters with my eyes moving a lot. That demo was only 5 mins, doh!
> I guess on the Vive and Rift I was not moving my eyes much.
If by "Samsung demo" you mean you demoed the Gear VR headset, I wouldn't be that surprised, as it's still just a phone on a frame. I would be surprised if the average phone had enough power to drive good enough visuals for a compelling VR experience and have an IMU with a fast enough update rate to not cause motion sickness.
This is part of the reason why I'm pretty stoked to see what the tech that GameFace Labs has been touting: It's a completely un-tethered experience like the Gear VR, but the latest version has the screaming-fast Nvidia Tegra X1, which gives you more power than you'd get with a phone-caddie headset, not to mention an actual, fast IMU to minimize motion sickness. I spent about an hour playing with one of their headsets a few months ago, and didn't get sick in the slightest.
Regarding motion sickness, though, another large component isn't so much moving your eyes, it's about your view angle changing gradually without your control, which throws off your vestibular system because what you're seeing is essentially desyncing from the angular momentum that you're feeling. Oddly enough, this issue doesn't happen with large, instantaneous changes in view angle. In the case of a first-person shooter, being able to change your view angle with the game pad *and* by moving your head tends to cause massive motion sickness - but if you modify the controls so that you can only look left/right with the pad, not up/down, and also make it so that each push of the stick to the left or right "snaps" your viewpoint around in 45-degree increments, there's next to no motion sickness at all.