Arc System Works has released Double Dragon IV for iOS via the App Store and Android via Google Play. It is free to download with access to the first mission. To play the other missions, a purchase is required.
Here is an overview of the game, via its store pages:
The story picks up after the elimination of the Black Warriors in Double Dragon II!
Experience all-new exhilarating action with the original old-school graphics! Use the art of Sou-Setsu-Ken to rescue the kidnapped Marian!
Plus, new enemy characters including ninjas, karate masters, and sumo wrestlers,none of which have been seen in Double Dragon before!
There are lots of extra modes, too! Cool new features fans have been waiting for! Playable enemy characters, Tower Mode, and even more!