The Feb. 2009 Nintendo Power has a small bit about the Black Knight in it. A couple interesting facts from it:

It uses woodcut-esque cut-scenes aside from the opening movie (like Sonic and the Secret Rings did with storybook scenes).

Shadow is Sir Lancelot, Knuckles is Sir Gawain, and Amy Rose is the Lady of the Lake.

Shadow and Knuckles are playable in the multiplayer battles after you’ve defeated them in the one-on-one duels in single player mode.

The multiplayer mode lets you either go sword-to-sword against up to three others in a free-for-all or you team up together to defeat a giant baddie as quickly as possible.

This time around I’ve scanned the entire article instead of just the images for you guys. Aren’t I nice? I suggest you still go out and buy the Feb 2009 issue of Nintendo Power to see the article for yourselves. It also has an interesting reader question. The reader mentions that Sonic X-Treme (the cancelled Sega Saturn game) kind of has a Super Mario Galaxy feeling to it. Chris Slate responds saying that he wrote a cover story on Sonic X-Treme for Game Players back in the day and does see a small resemblence now that he looks back. I wonder if Chris has any other inside info about the game from the press side of things…

Source Nintendo Power #238, February 2009