Nope, he's using pixelshader 3.0 at max, so no geo-shaders
I'm following this project for quite some time now, and every new video is more impressive than the videos before. Quite an impressive project.

You can find more info on the technical side of the game (plus some nice tips) here:
http://www.infinity-universe.com/Infinity/index.php?option=com_smf&Itemid=75&board=6.0