So, apparently if you click on locations on the globe, you'll get like a 30 second preview clip of what each area looks like. The music is different for the sun and the moon, and they show different clips for the difference in gameplay.
The sun music is quite upbeat with an eastern flair to it, that actually fits all the clips quite well. However, the moon stuff is some NICE jazz stuff with strings in the background. I am diggin' this.
It looks like the gameplay for the night clips is more toward the style of what Knuckles was in past Sonic Adventure games in terms of fighting enemies, but dropping the speed by half and not having you search for anything. Also, I was unaware that were-hogs had jelly arms.
EDIT: ok, that was just for 'Shamar - Locations.' Apparently there is a lot more music on the site.
EDIT 2: so besides the 90s pop-punk on the main page, all of the other music is quite good.