So I mentioned way back in the Wario Land comments that I eventually got to play it at Nintendo's booth. I got to do the first level, which is sort of the tutorial level, but with no irritating text to slow you down.
The first thing I noticed while playing is that the controls were impeccable. The second thing I noticed was that Wario moved way, way too smoothly to be a pixel art creation (like, say, the guys in Mega Man 9). He looked, frankly, like a hand-drawn cartoon character. I asked Nintendo's rep to confirm this or me, and they did-- Wario and all of his enemies had their movements digitally animated by hand, then imported into the game. Backgrounds appear to be a blend of digital art and pixel art.
They couldn't name the studio, but got back to me with it late last night-- and it seems Wario was digitally animated by Production I.G., a Japanese studio known for anime projects ranging from Ghost in the Shell to the famous anime sequence in Kill Bill. Does this make Wario Land a historic first? I can't think of any other game, offhand, that managed 2D without using pixel art for moving objects. If you can, please hit the comments.