Dragon Wang), though oddly, it never got a sequel until more than half a decade later, and that sequel never got released outside Japan, nor did it even come close to becoming as iconic as its predecessor.
There's a few reasons for this: Spartan X, while not the first beat em up, was a fairly early entry into the genre, and brought with it simple, fun mechanics and beautifully simple graphics that made great use of chunky sprites and limited colour palletes to depict a classic kung fu cinema-inspired setting. Where Spartan X 2 falls short is that it keeps the simple mechanics, despite the fact that 6 years had passed, and in those six years, the likes of Final Fight and Nekketsu Kunio Kouha-kun (among others) had totally revolutionised the genre, making Spartan X 2's single plane stages and one-hit enemies look old hat by comparision. That's not to say that the single plane beat em up was totally obsolete: 1988's Altered Beast, for example became an icon of its era by adding all kinds of new gimmicks and mechanics onto the idea (and by being a prominent Mega Drive launch title too, no doubt).
If you happen find a copy of the Famicom cartridge for a (very) low price, Spartan X 2 is a fun game to add to your collection, but otherwise, it's not really good or interesting enough to go out of your way to acquire.