The current navigation control for the free-movement section of the demo are not suitable for comfortable VR. Free-turning in particular will rapidly become uncomfortable, but variable-speed translation is also an issue. This is all down to the issue that any movemnt of the user's head position in the game world that is not directly 1:1 with the user's head position in the real world are likely to cause nausea, if not handled very carefully. Personally, the current implementation is bad enough that I generally close my eyes whoever I have to move, then stop moving before opening them again, in order to avoid nausea (though I am relatively sensitive to simulator sickness).
There is no one fixed solution to this problem, but there are many solutions that may be more or less applicable to various game area. Oculus' Best Practices guide (https://developer.oculus.com/documentation/intro-vr/latest/concepts/book-bp/) has some good information to use as a starting point, particularly the "Motion", "Simulator Sickness" and "User Input and Navigation" sections.
One techniques that works well for orientation is the use of 'quantised'/'snapping' rotation, where the controller (or keyboard/mouse) will only turn the player is instant set increments, usually of 45°. This avoids the forced movement of the scene causing vection (https://en.wikipedia.org/wiki/Illusions_of_self-motion#Vection) as there is no movement, jist an instant orientation change. Finer direction changes than 45° are implemented by the user physically turning their head.
The analog of this for translational movement is teleportation: the user looks at a spot in the world, then presses a button to instantly jump to that spot (sometimes with a few milliseconds of black screen in between to enhance the break in location). This is often implemented as holding a button to display the 'target' location as some indicator in the game world, and releasing it to teleport. This has been implemented successfully in games such as Epic's Bullet Train demo, Cloudhead Games' The Galler, etc.
If this is deemed immersion-breaking, there are options to allow more free-roaming movement while reducing (though generally not eliminating entirely) discomfort. One is to only ever allow one movement speed (no analog speed control) with instant acceleration and deceleration. Others include showing some variety of 'grid' in the environment that is fixed to the user, often in combination with desaturating/lowering contrast/etc the game world, to try and fool the brain into thinking they are stationary in the grid and the environment is being moved around them. This has so far had limited success.
Finally, loading screens are currently an issue: a static image stuck to the head (e.g. the pause after selecting the 'Trance/Binaural Session' option) is highly uncomfortable. If it is not feasible to display a tracked environment during loading, a pure black screen is preferable for comfort.
The actual Trance/Binaural Session is effectively flawless as it is for VR comfort, with no forced head movement or moving environment or horizon.
