Back to the Basics with some Panache
Mario's new moves include a butt stomp a la Yoshi in Yoshi's Island, a triple jump, and a wall-jump a la SM64. They are fluid moves and easily executed. I'm especially happy with the wall-jump as it's easier to pull off then the Metroid wall jumps and can be very fun to perform.
The levels are standard SMB levels--castle, desert, underground, underwater, hilly land, etc.--, but with some cool twists like pipes that launch Mario into the air, a launch pad thingy that makes Mario twirl helicopter blade style, and some other goodies I won't spoil. Some of the level can feel kind of short compared to open-ended gameplay style more prevelent in most games made nowadays, but they have highly replay value and good appeal in design.
There are some minigames that seem ripped from the SM64DS cart and some new ones that are decent but nothing eye-popping. The mini-games seem tailored to a younger audience.
I haven't played mulitplayer yet, but I know there's no CO-OP mode via the menu so that's kind of a disappointment. There's a battle mode. Not sure on the gameplay there, but from what I've seen of the videos of it it looks to be very similar to the gameplay of the core game itself.
After playing for 2 hours I began to realize that the gameplay isn't that fresh, but it's solid and enjoyable enough to make for a perfect portable game.
One major complaint is the save system which seems to be centered upon completing a mini-castle or castle or having 5 star coins so Mario can unlock a mushroom house. This is fairly annoying, but nothing major.
All in all, NSMB is a fine addition to the legacy of the Mario Bros.