The level itself doesn't look so jaggy around the edges now.
The pictures are "bullshots" though. If you don't know what that is, it's a commonly used marketing tactic by game companies for last gen games to make them look better in stills on modern computers. They basically take the game and up the resolution(which is the case here) and add 16X AA(which is also the case here) in stills. The game itself will still look "jaggy" when you play it because the Wii can't output 16X AA or display anything above 720X480 by design.