Mortal Kombat: Deception is a developed and published by as the sixth installment of the (MK) video game franchise. It was released for the and in October 2004, for the in March 2005 and later for the under the title Mortal Kombat: Unchained in November 2006. Mortal Kombat: Deception follows the storyline from the fifth installment, . Its story centers on the revival of the Dragon King , who attempts to conquer the realms featured in the series after defeating the sorcerers and , the main antagonists in the previous game, and the Thunder God , defender of Earthrealm. The surviving warriors from the previous titles join forces to confront Onaga.
The game's arenas are similar to those in , but include new features. Some have weapons which may be picked up and used. Others are now branching, meaning that you can knock the opponent out of the fighting area in certain locations, and then continue the fight in a new area. Most levels now have deathtraps, which instantly kill any player that gets knocked into them. The game also introduces the "Combo Breaker", a system which allows players to interrupt up to three times per match. In contrast to Deadly Alliance, in which characters had only one , the Deception characters have two Fatalities and a suicide move. The latter is used when the phrase "Finish Him/Her" is shown on the screen and the player is about to lose.
Deception introduces two that use MK characters, "Chess Kombat" and "Puzzle Kombat". The Konquest mode returns, but has been expanded into a roaming adventure game with its own plot.
The "Krypt" returns from Mortal Kombat: Deadly Alliance and serves as an interface to access extra content hidden in "koffins" (actual coffins named with the series' trademark misspelling). In Deception, the size of the Krypt was reduced from 676 koffins to 400 koffins. Some koffins also have locks that require keys which can only be found in the Konquest mode. The Krypt in Mortal Kombat: Deception includes twelve bonus characters (which was cut down to six characters in the GameCube version)