In the demo, I had to click on the screen a couple of times to get the dot to start moving around. Then, it seemed to want to follow my mouse quite a bit as I moved and clicked.

I was able to greatly move the red dot when I say closer to the webcam, really opened my eyes, and moved left to right, but the action was flipped for me — looking left moved the dot right, and vice versa. (I'm using an Apple Cinema Display… I've had issues before where it automatically flips the screen around in some cases.)

Although not very accurate, it's certainly an interesting experiment.