The quality seems to be way less than a gigapixel. It would be interesting to see a corresponding dslr gigapixel image.
The ball optic is very interesting though.
Pixels are half the story. Cellphone cameras for example boast their megapixels but if the optics suck there's not much value gained from all those extra pixels.
In those demonstration shots you can still make out faces from the far side of the stadium even though there's considerable noise.