It's mahjong, what did you expect?
3D Mahjong is shockingly the first mahjong game available for DSiWare in North America. It offers everything you'd expect from a mahjong game on the DS, with 50 different tile layouts and touch screen controls, but finicky control and a sense of aimlessness make the game a serviceable but bland experience.
The game is controlled exclusively on the touch screen, and both screens offer a different view on the layout of tiles. The controls work, but sometimes you have to select a tile multiple times before the game registers it. You have to be very deliberate with your movements, which can slow down the pace of the game considerably.
The 3D aspect, which is shown on the top screen by default, is barely worth mentioning. Basically, the top screen shows a view of the tile set in 3D. You can control the angle of the 3D poorly on the touch screen, but other than that it's not helpful at all.
The varied tile layouts make for a new type of challenge each time, and even just one of the layouts can have more than hundreds of variations. Unfortunately, there is no sense of progression throughout the game. Every single tile set is unlocked at the start, and every time you complete a puzzle, all that happens is a small overlay that says congratulations and tells you how long it took you. There is no sense of accomplishment, and no record of your achievement. Even the solitaire games that come with most PCs shoot off virtual fireworks.
In addition to mahjong, there are also two additional modes dubbed Memory and Matching. These are exactly what you'd expect. You can also change the background and tile graphics, which is cool, especially if the traditional Chinese tiles confuse you.
The presentation might be lacking, but there's still a good deal of content tucked away in this package. If you're looking for a cheap and fun mahjong experience for your DS, then 3D Mahjong is a worthy purchase. However, if you're looking for a puzzle video game experience, you're better off with a game that offers more than just congratulations.