Double Dragon II can be played by up to two players simultaneously. The game offers two modes of play, which differ only in whether or not the two players can hurt each other with their attacks.
The structure of the game is completely different. While the first stage resembles the one from the arcade version, the level designs deviates completely from Mission 2 and onward, with scenes set in a variety of new locations such as the interior of a moving helicopter, an undersea base and a series of trap rooms.
There are a total of nine stages in the NES version. Before each stage, a cut-scene is shown consisting of still imagery and text which provides the setting of the stage. The enemy characters are roughly based on the ones featured in the arcade version, but some of them carry different weapons or have new fighting techniques, such as Rowper’s ability to throw boomerangs at the player.
Besides the final boss, the other enemy characters that are introduced in this version are the “right-hand men” that serve as recurring sub-bosses from Mission 2 and onward, and the ninjas that appear at the end of Mission 2 and later on in Mission 8.
The game retains the directional-based combat system from the arcade version. Unlike the first NES game, the player has full access to Billy or Jimmy’s entire repertoire of moves from the beginning. In addition to the Cyclone Spin Kick introduced in the arcade version, two additional special moves were added to the player’s set of techniques, the Hyper Uppercut and the Flying Knee Kick.
These two moves are performed while the player’s character is crouching, which is only possible after landing from a jump or recovering from a fall.
No more than two enemy characters will confront the players at any given time, and they will both be the same type of enemy. Melee weapons have been changed slightly to include chain whips, knives, steel pipes, and grenades. Whenever the players defeat one group of enemies, all weapons on the screen disappear, including any that the players are holding.
At the easiest difficulty level, the game ends after the third stage. The intermediate level allows players to complete all but the ninth and final stage; the hardest level grants access to all stages and the confrontation with the final boss.