[QUOTE=mbd36]What was wrong with the original US release of "Final Fantasy IV"? (I assume you are referring to the American "Final Fantasy II".) Me and my friends all loved it at the time.[/QUOTE]
It's based on the Japanese "Easy Type" version which nerfs the difficulty and significantly affects the balance of the game. Put shortly, Final Fantasy II (SNES) is way, way too easy. Final Fantasy IV was always supposed to be difficult--the bosses are hair-raising, nightmarish puzzles on other versions of the game; in FFII (SNES), I never met a significant challenge.
Secondly, bugs. Quoting from the FF Wiki:
In the original SNES version, there are various bugs concerning equipment, ranging from weapon effects that never take effect, and the Avenger weapon that, among many other glitches, fails to update the character's attack stats to those in the Avenger weapon, retaining whatever stats the character had in the previously equipped weapon, to weapon duplication glitches.
An especially hazardous glitch is the possibility of completely losing the Lunar Whale airship on the moon. Another fatal glitch is the Save Glitch, which erases all save files on a cartridge.
There's a pretty long list in addition to these. Subsequent releases have addressed these problems.
Thirdly, the translation. The guy who worked on it wasn't actually fluent in English, which is why the script barely makes sense. Moreover, since English text requires more data than Japanese, a lot of content had to be cut for the U.S. release.
Final Fantasy II is the worst way to play one of the best games ever made.