Yet another Hudson soft game, Shinjinrui is a novel take on the vertical shmup genre in that instead of controlling a plane or a space ship, you're a caveman walking on the ground. The same is somewhat similar to the Squaresoft game King's Knight, but is much better.
Due to the quality and simplicity of the mapper, Shinjinrui is often featured on bootleg multicarts with options to play it with different power ups unlocked from the start of the game. That's how I first experienced it myself.