"1 - The lenses that provide the wide field of view on a single LCD screen also magnify the pixels. If you have good eyesight then the RGB sub-pixels are very visible.

"2 - Slow pixel response (time to go from light to dark) causes visual detail to blur when when changing view direction quickly. The blur detracts from the sense of 3D.

"3 - No acceleration detection, only orientation, so you can't strafe your view by moving your head to the side.

"These three problems, combined with apparent motion that does not match what your own proprioceptors are telling you, can cause some people to get nauseous in certain demos. Some people who were dizzy from one demo were not affected by others.

"Another drawback which probably doesn't contribute to disorientation is that the LCD has low contrast range between bright and dark. Not surprising given that you've got a low-cost LCD right in front of your eyes, but nevertheless one aspect that could be improved upon in the future."