How is Japanese Zelda II different from the NES version?

Zelda II began in Japan on the Famicom Disk System on January 14, 1987, almost two years before the NES cartridge reached North America in December 1988, and the game Nintendo shipped west was not quite the game Japan played.

The deepest difference is the levelling. In the Japanese version, Link's three attributes, Life, Magic and Attack, cost the same experience to raise at each level. The international version repriced them, Life cheapest and Attack dearest, herding players toward a fixed order. Worse, saving in the Japanese version drags all three attributes down to the level of the lowest one: a saved game keeps your crystals and items, but an unbalanced Link is levelled flat.

The presentation differs too. Japanese dungeons are built from grey and green brickwork where each NES palace received its own colours; two bosses, Carock and Barba, wear different designs; and the FDS disk's extra sound hardware gave the title music elements the NES port had to drop. The famous Ganon silhouette on the game over screen is an NES addition: the disk original fades to plain black text.

For collectors the point is that the Japanese disk is not a translation but an earlier, sterner edition of the game, the same reason this Library documents regional versions as separate objects.