Apparently Nintendo appreciates their Japanese fans more than their American ones...because the Japanese Mario Galaxy 2 site
has new screenshots and gameplay videos on it. But this is the internet! Aha, didn't think of that one did you Nintendo? I can go look at those videos any time I want!
In all seriousness it's pretty easy to poke around the site and find the new media even if you don't read Japanese. People have been writing Galaxy 2 off as a glorified expansion pack but considering how much critics fawned over the first game, I don't see how that's a bad thing. I was probably one of the few people who was a little disappointed in the original Mario Galaxy; I liked the more somber story and the Rosalina character, but I felt that the new gameplay ideas weren't taken far enough and the simpler camera controls were kind of insulting.
This is probably why I'm more excited for the sequel--it's supposedly much harder, and with the framework down and less emphasis on the story, Miyamoto and his team have really focused on exploring the limits of the micro gravity planetoid gameplay. The new videos indicate that the worlds are even crazier, Mario has new upgrades like a rock and cloud suit, and the ideas are more fanciful and less realistic, which is just fine for a Mario game if you ask me.