Hah gyrene, that is true; but it actually is immersive enough that after a very short while; being aware of the keyboard and mouse becomes instinctual. But it is a total kick in the butt to find the controllers/etc to begin (only a small hole at the tip of your nose).
Karnak, I did not find any problems with lack of immersion; infact it has me a bit worried if they are hoping to get kids plugged into these kind of things, it's gonna be much worse then it is now for "getting out of the game" if people have this as a normality. Pretty sure this stuff could cause severe adverse reactions to outside interruptions for some. Dev kit could use a slightly larger lens to fully enclose your peripheral vision, but its just a dev kit (low res/etc).