Sorry to get off topic, but I've heard a lot of NSMB bashing lately, and I just don't agree. The team set out to recreate the feeling of the original Super Mario Bros, and it did so brilliantly.
Comparing it to later games from the Mario series, it may seem incomplete or whatever, but viewing it as an homage to Super Mario Bros, it is outstanding. And in fact, I think it stands nicely against others in the series, too. By reducing the game to the basic Mario elements, Nintendo brings the focus back to platforming: you can't just fly over the challenges, and the designers focus on amazing platforming design.
If you go in expecting a sequel to SMW/SMB3, then you'll be disappointed. If you go in expecting a remake of Super Mario Bros. 1, you'll be very happy. If you think flying is key to a good Mario game, you'll be disappointed. Personally, I stopped thinking that flying, Yoshi and suits were what makes Mario games fun a long time ago, but that's not true for everyone, I know.