The SMS isn't a platform I have a lot of experience with.
The SMS is a true oddball. Blessed with powerful arcade ports, it got bashed for it with the usual anti-arcade trash talk like "with a few continues, game X can be beaten during one afternoon" or "game Y has many unfair sequences, where energy loss is unavoidable" etc. Evidently video game magazine editors never understood arcade games and never will. They sure know their creditfeeding, though.
Consequently many titles were criminally underrated, like the very good port of DECO's Captain Silver or the very ambitious port of Shadow Dancer. Anyway, the fact that it was so popular in Europe made it possible, that PALestine was endowed with some of the greatest exclusives, like Power Strike II, Asterix or Dragon's Trap, old Nippon could only go green with envy. A historical precedent, no less.
Shinobi is pretty great once you get over the fact that it's not really a port of the arcade game. It kinda does that Konami did with their nes games where instead of making a crap port they did something that plays to the strengths of the system. It took me a while to appreciate it but it's a great game.
That's brilliant understanding of the SMS concept. Similar can be said about the SMS version of Ninja Gaiden, Enduro Racer or, maybe most prominently, Ancient's first Sonic and SMS Castle of Illusion, which both feature a different level design, such good ones in fact, they rival the Mega Drive originals, arguably even exceeding them.