Randil, there are differences, the two biggest being that instead of saves, this game was password-based (an insanely long chain of hiragana, like 52 characters or something crazy like that) and, most significant speedrun-wise, the intro starts when the wounded Moonbrooke soldier makes it to the starting castle whose name I can't recall; every other version of the game, including the Japanese remakes, features an intro showcasing the attack on Moonbrooke, the slaying of its king and the escape of the one soldier, which theoretically would extend a technical "run" by 2 to 3 minutes over the Japanese version. The original game had cross iconography, too, a no-no in Nintendo's anal-retentive days, so the US NES version replaces them with Stars. IIRC these are the only significant changes to the game.

om, nom, nom... blech, stale!