I'm sure many of you here have played this on the NES.This is my second favorite Nintendo game of all time and my 7th favorite game ever, although it's working it's way up the ladder. It's 100 times better than the Xbox 360 version and has an EXCELLENT soundtrack. The game satisfies your ninja needs.
You play Ryu Hayabusa, a ninja who finds a letter by his recently missing father, Ken, telling him to go to America and meet with an archaeologist Dr. Smith. Dr. Smith tells Ryu that two statues hidden by Ryu's father and the doctor have the power to end the world - if united. Ryu ends up in South America and battles Jaquio, the evil mastermind responsible for the attack on Ken Hayabusa.
It's pretty damn awesome and loaded with sword-slinging action, plus bad guys with bats, clubs, boxing gloves, and more.