For some reason, all the ways I can think of starting to describe Shinobi III: Return of the Ninja Master involve Essence of Ninja packed tightly into a 16-bit cartridge by ninja highly trained in the art of packing Essence of Ninja into 16-bit cartridges.
Shinobi III was released by Sega for the Genesis in 1993. While the Shinobi series is broader and more complex than even I was aware of prior to researching this article, RotNM has one very key distinction over its predecessors and even some successors. Previous Master System and Genesis titles were about walking around slowly and throwing shuriken at things. Previous Game Gear titles featured flips, ceiling-walks, and slashing stuff, but never as the same character. They were also about rescuing Power Rangers and recovering magical rainbow crystals. The most recent PS2 game is about some magic demon wizard stuff and getting killed by your own sword.
Shinobi III, by contrast, is about flipping out and killing people. More specifically, it's about flipping out and killing explosive zombie-soldiers armed with automatic weapons, slicing up giant bioengineered meat-golems, horse-stomping ninja super-soldiers, jetboard-flying-kicking heavily armed marine tank robots, destroying robo-godzilla, scaling cliffs by jumping between falling boulders, navigating entire areas using only wall-jumps, katana-ing heavily armed airships out of the sky, and I think something about an evil super-ninja trying to take over the world, but that's only the plot, and if you know what the plot is, you obviously aren't very familiar with the concept of Ninja-ing.