Ninja Combat is a 1991 side-scrolling action game, developed by Alpha Denshi and published by SNK.
It was one of the launch titles for both the Neo Geo MVS (arcade) and AES (home) systems. Among action side-scrolling games, it is notorious for its high level of difficulty and odd design and gameplay ideas.
The story, set in the year "199X", follows the twin ninja warriors Joe (ジョー) and Hayabusa (ハヤブサ, lit. "Falcon") (curiously sharing their names with Joe Musashi and Ryu Hayabusa), who are waging a battle against an evil ninja clan Kage Ichizoku (影一族, lit. "Shadow Family"). Their mission is to fight their way into the enemy home fortress, Ninja Tower (ニンジャタワー, "Ninjatawa"), which has emerged from the ocean in the center of New York City, to once and for all defeat the Shadow Family and its leader, the long thought-dead demon sorcerer Genyousai, and crumble the Ninja Tower.
Source: Wikipedia, "Ninja Combat", available under the CC-BY-SA License.