Pure, old-school fun!
It doesn't mix things up too much.
But in this instance, thats a good thing.
It's classic 2D Platformer Mario with 3D visuals, which look awesome.
Theres a bright colorful world filled with mushrooms, koopa-troopas and all sorts of things waiting to suck you in here.
The single player game while not difficult on the whole, offers enough challenge to make it worth your time. And the multiplayers the icing on the cake.
With one player as Mario and the other Luigi the players race to grab gold stars and whoever grabs the set amount or the most before time runs out wins.
You can try to slow down or destroy the oppisition with various power ups including the classic fireflower and some new ones.
Such as the mega-mushroom, grabbing this will dramatically increase your size allowing you to crush pretty much anything in the way. All you really gotta look out for while it's in effect are pitfalls.
Then theres the mini-mushroom, which does pretty much the oppisite of the mega-mushroom, in making you small. While real tiny you can jump a little higher and walk on water, but it'll take only a single hit to kill you!
And my favorite the Blue Koopa Shell. Duck down in this and you'll be protected from the opposing players fireballs, but becareful because they can kick you! If your lucky though you may just hit a wall and rebound back.
It's a lot of fun.
Theres also a good variety of stylus based minigames to play, but they won't keep your interest for that long.
On the whole NSMB doesn't do anything new, but it revitalizes something old and makes it worth grabbing.