Mortal Kombat, commonly abbreviated MK, is a series of fighting games created by Ed Boon and John Tobias. For the first four renditions of the series, the games were picked up by Acclaim Entertainment for the home console versions. Then beginning with Mortal Kombat: Deadly Alliance, Midway Games exclusively created home versions of Mortal Kombat up until Mortal Kombat vs. DC Universe. The franchise had been sold to Warner Bros. in July 2009 and became a part of the Warner Bros. Interactive Entertainment Branch. The series began originally as a game based on the popular actor martial artist, Jean-Claude Van Damme. The idea fell through and Mortal Kombat was born instead. As a result of its success, Mortal Kombat has spawned many sequels and has been spun off into several adventure games, films (animated and live-action) and television series (animated and live-action). The Mortal Kombat series has inspired several songs, including "Techno Syndrome," otherwise known as the "Mortal Kombat Theme." Other spin-offs include various comic book series, a card game and a live-action tour.
Mortal Kombat has been compared to other fighting games, most often Street Fighter. The original 5 games, Mortal Kombat, Mortal Kombat II, Mortal Kombat 3, Ultimate Mortal Kombat 3 and Mortal Kombat Trilogy were styled in a 2-D fighting fashion with gameplay consisting of five buttons that were high punch, low punch, high kick, low kick and block. Reviewers have stated that because of this the characters are only differentiated by their special moves. In fact, some reviewers have criticized that the "bewildering array" of special moves in comparison to other fighting games has resulted in too little focus on regular moves.
The series is especially noted for its realistic digitized sprites (which differentiated it from its contemporaries' hand-drawn sprites), and its high levels of blood and gore, including, most notably, its graphic fatalities—finishing moves, requiring a sequence of buttons to perform, which, in part, led to the creation of the ESRB. The series itself is also known for using the letter "K" in place of "C" for the hard C sound, thus misspelling the word "combat," as well as other words with the hard C sound within later games in the series. Early games in the series were infamous for the prominent use of palette swapping to create new character sprites.