Joystiq [Nintendo]

Shadow Dancer is a spinoff or sequel or something of Revenge of Shinobi, starring a very Joe Musashi-like ninja (who, in the U.S. is Joe Musashi, but is Joe Musashi's son in the Japanese version) who is on a mission to avenge his friend Kato's death by killing as many other ninjas, green-armored discus guys, and sci-fi marksmen as possible. Joining him on his mission is Kato's dog Yamato, who also seeks revenge, or is just a helpful dog.

Shadow Dancer plays much like its predecessor, except that Joe can only sustain two hits at most and has unlimited shuriken. There is also more of an emphasis on two-tiered design; by pressing up and jump, Joe can jump to a higher platform or, in some cases, deeper into the stage (behind a fence in one memorable example). The goal of the game is to rescue hostages throughout the level, much like another famous Sega sidescroller of the time. There's also an enjoyable bonus level in which Joe jumps off the side of a building and throws shuriken at other ninjas as they climb up. It's like Galaga in reverse, with crazy people.
Most importantly, there's a dog. By holding the attack button, Joe can release Yamato, who goes after the nearest enemy and gets into a struggle. While the dog is fighting, you can walk right up and kill the guy. This is especially great for jerks with pistols, who hide behind crates and pop up to shoot at you. It doesn't work so well for tougher enemies, who render Yamato useless by hitting him and turning him into a puppy for some reason. Getting a powerup item (which also turns Joe's shuriken into fireball-like things and powers up his hand-to-hand skills) restores Yamato's full size. It's important to note here that unlike weak old Joe, Yamato cannot be killed. He is an invincible ninja dog.