I dunno about the judges but Frank Cannon from Arstecnhica played it:
"The level I played involved the traversing of a platform-laden maze with the goal of collecting a variety of gray stars scattered about the field."
http://arstechnica.com/journals/thumbs.ars/2007/07/13/ars-at-e3-hands-on-with-super-mario-galaxy
Jeff Gerstmann from Gamespot played it too:
"While it wasn't shown in detail at Nintendo's press conference, there is a pretty cool playable demo of the tentatively titled Super Mario Galaxy here at the Electronic Entertainment Expo."
http://e3.gamespot.com/story.html?sid=6150125&pid=915692
And so did the guys from IGN:
"In today's demo we had a chance to take a look at four different stages, each set within a different 'Galaxy.'" (and take look at the first 3 pages of videos)
http://wii.ign.com/articles/803/803958p1.html
It didn't win, but it was definitely playable, at least 4 levels, it seems.
