Double Dragon is a classic beat-em-up that Is legendary. The story is two martial artist brothers, Billy and Jimmy Lee, have to go save Billy's girlfriend, Marian, who has been kidnapped by the Black Warrior gang (a.k.a. the Shadow Warriors). However, when the game was ported to the NES, the story changed in order to fit the fact that two player co-op was removed due to the console's technical limitations, as Jimmy would be the leader of the Black Warriors while Billy had to rescue Marian.
Depending on the version played, there will be some major differences. The similarities are the game is four levels (which are referred to as missions) long and for the arcade, it has three buttons, punch, kick, and jump (in the NES port, the punch and kick buttons are on the A and B buttons, with jumping being done by pushing them both at the same time). Also, the game has a colorful cast of enemies, from the whip-wielding Linda to the giant Abobo, and weapons that can be knocked out of enemy hands, and picked up for your own use. The one thing that keeps it from being perfect is its difficulty, as it can be unfair at times (especially in the final level, where you have to deal with a trap wall that can do massive damage). But this is an awesome video game that needs to be played.