Well it looks like now no body has any right to complain about the games help feature.
http://kotaku.com/5374432/kind-code-demo-shows-new-super-mario-bros-on-auto+pilotIn case anyone is to lazy to click on the link, what happens is when you die eight times in a level, a green box will appear at the beggining. If you hit this green box, a computer-controlled Luigi will appear and go through the level on his own. During this time the player can take control of Luigi anytime on there own if they want. Oh and this computer Luigi will only take the basic path to complete the level. Any secrets that might be in the level, the computer will not show you.
So unlike what some people originally thought, the game actually encourages the player to play the game and people can't just use the help feature to skip to the end without even playing the levels. Plus even if they do use it, they won't be able to truly complete the game since this feature doesn't show any of the hidden secrets that Mario fans love to find.
Plus like others have said, the levels in this game look harder then those in the DS New Super Mario Bros. Which once again shows that this feature was a great thing since it seems like it allowed Nintendo to make the game more challenging, while still making it accessible for less skilled players.