Mortal Kombat: Deadly Alliance is a 2002 fighting video game developed and published by Midway for the Xbox, PlayStation 2, GameCube, and Game Boy Advance. It was the first all-new Mortal Kombat fighting game produced exclusively for home consoles, with no preceding arcade release. It is the fifth main installment in the Mortal Kombat franchise and a sequel to 1997's Mortal Kombat 4. Its story focuses on the eponymous alliance between sorcerers Quan Chi and Shang Tsung and their schemes to revive an ancient army to conquer Outworld and Earthrealm. The game is the only main installment not to feature series protagonist Liu Kang as a playable character. It is also the first game in the canon series to not have the involvement of co-creator John Tobias, as he left Midway in 1999 to pursue other interests.

In addition to the original Game Boy Advance Port of Deadly Alliance, a second version entitled Mortal Kombat: Tournament Edition was released on August 25, 2003. Tournament Edition featured characters omitted from the first port, along with characters not present in the other versions such as Sektor, Noob Saibot, and Sareena.

Like all of the Mortal Kombat games, Deadly Alliance focuses heavily on its fighting modes. The gameplay is completely different from that of previous entries in the franchise. Each character now possesses three individual fighting styles,[1] generally two hand-to-hand styles and one weapon style (except for Blaze and Mokap, who received three hand-to-hand styles and no weapon style) which players can switch between with the push of a button. In previous games, aside from "dial-a-combos" all the characters fought virtually identically, with only special moves to differentiate them. The number of special moves per character (usable in any fighting style) has also been reduced, varying only from two to four for most, thus forcing the player to make use of the improved fighting system. The characters can no longer run, and there is no run meter. However, while still limited to only moving into the background and foreground, movement in the third dimension is much easier and can be used continuously (in Mortal Kombat 4, sidestepping was mapped to two different buttons and could be performed at a rate of about one second). To prevent fighters from leaving the arena, boundaries that are otherwise invisible appear when a fighter is knocked against the edge.

Characters models became more realistic. Flesh will move or jiggle on a character as he or she moves around. Environmental interaction is present, but infrequent. Several levels include obstacles—such as pillars or statues—that can be shattered to damage an opponent standing near one. There is just one Fatality per character, while the previous games included many ways to finish the opponent. Along with Mortal Kombat X (until the XL patch added them to Mortal Kombat X), it is the only other Mortal Kombat game that does not include Stage Fatalities, although the Acid Bath level still possesses special acid-vomiting statues called Acid Buddhas that do damage directly to fighters that stray too close to them.

Deadly Alliance introduces the Konquest mode, which expands on the storyline and acts as a tutorial for each character. The Konquest mode consists of a series of missions to complete with each of the characters. In between each sequence, a video of a monk moving between various locations on the path of Konquest is shown, but this has no actual bearing on the gameplay itself other than to simulate the sense of a journey. After completing eight initial "kombat tasks" with Sub-Zero, the player is instructed to complete a specific set of tasks with each character, which vary from performing difficult combos to defeating opponents. Each series comes with text instructions that include a basic storyline that delves further into each character's background and motives. The characters Blaze and Mokap can only be unlocked by completing all stages of konquest. Upon completing each mission (of a starting difficulty for each character that increases per mission), the player is rewarded with a number of "koins" that act as the in-game currency to open koffins in the krypt and unlock secrets in the game.

The krypt is a feature in which the player can buy extras with koins earned in regular play and in konquest mode. The krypt consists of 676 "koffins" arranged in a square format with each designated alphabetically by a two-letter designation (AA–ZZ). The koffins are filled with a vast number of secrets and unlockables. Each koffin has a different designated price, listed in a number (anywhere from 1 up to the thousands) and type (Gold, Ruby, Sapphire, Jade, Onyx, and Platinum) of koins that it would cost to open the koffin. The Krypt includes unlockable characters, arenas, and alternative costumes. Also included among the koffins are various videos, images, concept sketches, and the entire Mortal Kombat Collector's Edition comic book. Some koffins contained koins that could be used towards other koffins, others contained hints as to where other items were located, and others were even empty.

Test Your Might, the original minigame of the Mortal Kombat series, returns for the first time since the original game, and a variation, Test Your Sight, is also included. In Test Your Sight, the character stands in front of a set of cups, and the game shows the player which cup contains the Mortal Kombat logo icon. The cups then begin to move in a random order, and by the end one has to select the cup containing the icon. As the player progresses through the minigame, the number of cups increases, as does the speed at which the cups move. At higher levels, the camera would even move in order to make it more difficult for the player to keep track of the movement of the icon. Succeeding at both Test Your Might and Test Your Sight rewards the player with koins.

The Game Boy Advance-only Mortal Kombat: Tournament Edition adds three modes: Survival, Tag Team and Practice, as well as weapon Fatalities. Although both of the GBA versions feature 2D sprites, Tournament Edition was the first portable Mortal Kombat games to feature 3D style gameplay.