The folks over at GameSpot have made it to the Games Convention 2007 in Leipzig, Germany, where they got to check out Ultimate Mortal Kombat on the Nintendo DS. From the article:
Ultimate Mortal Kombat 3 offers the 19 fighters from the original title, with three unlockable characters taking the total to 22. By default, punch buttons have been mapped to the X and A buttons, with kicks on Y and B, and block on the right shoulder button. As we've discovered with previous fighters on the console, the buttons can be a little fiddly and awkward during prolonged use, but it's still possible to pull off the special moves with a little practice. The game also offers a fairly lengthy challenge thanks to the novice, warrior, and two master levels.

Puzzle Kombat is a game much in the mould of Columns and Tetris but with a fighting spin. Sets of two coloured blocks fall down the screen, and the aim is to arrange blocks of one colour together. Then, every fifth or so time, one block will fall that makes all interconnected blocks of one colour disappear. This then charges up a special move meter that can be used by the fighters on the top screen to knock one another out.

What really impresses about the package is how Midway has implemented local and online wireless multiplayer for both games. Two players can link up locally using two carts or game sharing, and you can also use the Nintendo Wi-Fi connection to play people across the world. The game saves single-player and multiplayer high scores to the cart, and you can set up user profiles, too.
Not to speculate, but one can infer from the article that if it saves high scores, it would most likely will save the unlocked characters as well - meaning that once you use the Ultimate Kombat Kodes unlock Ermac, Classic Sub-Zero, and Mileena, you'll have never have to do so again. To read the article in its entirety, click here.