• Character selection: Choose from 22 fighters with different abilities. You also have secret methods to allow playing additional fighters. 
• Fighting action: Pull off all the classic Fatalities, Brutalities, Friendships, and Babalities! Finish Him!
• Multiple environments: Choose from tons of environments to fight in, including Scorpion’s Lair, Jade's Desert, Kahn’s Kave, River Kombat, Noob’s Dorfen, and more.
• Fighter variety: Each character has their own good or evil motives and a common goal—the destruction of Shao Kahn!
• Multiplayer modes: Play a variety of multiplayer modes including the new Challenger Versus Mode which allows you and three other friends to battle it out in a "winner-stays-on" style tournament.
• Detailed leaderboards: Xbox Live® captures the player's win and losses both for all time and for the current week.
• Twelve achievements: The UMK3 achievements offer rewards for both the novice and expert players.

From: Xbox.com