So I played the NSMBU demo at Walmart- Is it supposed to be nearly the exact same visual wise as the Original?

[Barozi]

From what I remember Digital Foundry said that the lighting is improved and it's obviously in a higher resolution.
I probably wouldn't notice much of a difference either. While I did play NSMBWii on a real Wii at a friends house once, I completed the game at home on the Dolphin emulator.