Also:

BTW, the original Kunio-Kun (River City Ransom is the a westernized version of the third game) game was made by the same guy that went on to make Double Dragon and some of the Kunio-Kun were released as Double Dragon games in the West. Double Dragon cameos have actually been common in Kunio-Kun games to the point they take place int the same universe licences willing.
Plus, WayForward made Double Dragon Neon.