Billy & Jimmy Lee

Billy Lee and Jimmy Lee are the two main characters in Double Dragon. They fight off against various gang members through the streets of a city and various other locations.

Their appearances have changed throughout the life of the series, usually swapping between hair color. Billy Lee originally having brunette hair and darker skin and Jimmy Lee having Blonde hair and lighter skin. As the series went on in some games Billy's hair was changed to Blonde and Jimmy's to Brunette. Such titles as "Super Double Dragon" the twins' hair styles has changed as well having Billy with a brunette laid down style and Jimmy with a blonde high-cut style. In Double Dragon 2: The Revenge, Jimmy wears a white outfit instead of his trademark red outfit.

The gameplay in most of the games takes place in a pseudo 3D perspective like in Renegade and later beat-'em-ups, in which the player character can move in four directions but are always facing left or right. The player can perform a variety of unarmed fighting techniques against their enemies, as well use melee weapons such as baseball bats and throwing knives normally obtained from enemies. In some installments, there are techniques that can be done in combination with another player.

According to the supplementary materials for some of the games, Billy and Jimmy Lee practice the fictional art of Sōsetsuken (双截拳?, "Twin Intercepting Fists"), a nod to Bruce Lee's fighting method of Jeet Kune Do, meaning "Way of the Intercepting Fist". Some of the enemy characters take their names from Enter the Dragon such as Williams and Roper from the first game, as well as Bolo and Ohara in certain versions of Double Dragon II: The Revenge. Additionally, the packaging artwork of Double Dragon Advance is based on the climatic fight of the Bruce Lee film Return of the Dragon.