Unreleased in Japan! Brand new, unopened, still in shrink wrap. Ultimate Mortal Kombat.

Ultimate Mortal Kombat

This game is not only UMK3, an updated version of MK3, but also includes the mini-game Puzzle Kombat from MKD/MKU.
It's a truly delicious port, offering two games in one!
Also, taking advantage of the DS's dual screens, it helpfully displays the FATALITY commands (though distances aren't specified).
With this momentum, I hope they'll bring over Trilogy next... !

Most of the Mortal Kombat series hasn't been released in Japan, and this is no exception.

This is also the first game in the series I've purchased.

Well, the content is as I'd heard, but due to the graphic limitations, the fatalities are mostly comical. Haha.

Compared to the more recent games in the series, which have a lot of bloody fatalities, this is much more restrained.

Also, as others have mentioned, the CPU is too strong.
The character Motaro, a centaur, is a particularly difficult opponent.

It requires a lot of player skill, so you'll likely lose on your first try.

However, it's undoubtedly the best fighting game on the DS.