Overall I would say this is the best game I've played so far (out of a whole 5), but it's still really an NES-hangover game.
Story/Characters: The story is a strong part of the game. It starts out relatively slow, but odd things keep popping up here and there. It centers around a group of people who are immortal, and who have no memories aside from their names. Huge pits have appeared around the world and monsters are coming from them. Who are these mysterious immortals? Why are the monsters coming? These initial questions deepen into further mysteries, and the ultimate reveal is fairly satisfying. Some of the plot developments cause a little head scratching, but overall it makes sense. The ending is bittersweet as well.
Now, it's still a pretty rudimentary story on the whole, but for 1992 it's pretty good.
World: The world is based on Greek mythology. You visit many of the well known cities, such as Troy, Athens, Sparta, and the Persian lands. Many of the gods are present, and you will fight a number of famous mythological monsters as well. If you are a fan of this kind of thing, it's a lot of fun.
Game Flow: I would say this is above average for a game of this era. There are some places where I think they could have provided more clues to where to go next -- a lot of times you can just explore where you haven't been, but in some cases you have to backtrack to specific places that aren't well identified.
The endgame is a big problem, though. The last few bosses suddenly take 1 damage from every non-critical attack and do enormous amounts of damage, sometimes to all party members. You can overcome this with buffs, but I had to grind and exploit a bug to beat the final boss. Since the grunts get stronger as you raise levels (but give the same XP), you also die a lot in the final dungeon trying to level.
System: The game is very derivative of Dragon Quest so if you've played those, you'll find yourself at home here. One welcome quality the game has is that everyone has lots of MP so that casting spells, even in grunt battles, is actually feasible. The game also has a pretty good AI system, which is good, since sometimes you have to use it. The game assumes that the main character is giving orders to the others. So if the main character is paralyzed, asleep, or unconscious, the AI takes over until the main character is back. Sometimes it's fun to fight alongside the AI, though. In one early boss battle the main character was KO'ed on the first boss attack and I had no revive items or spells, so the entire battle was AI.
The magic system has you visiting temples around the world dedicated to various gods, and gaining that power. Unfortunately this means you have to revisit all the temples every time you get a new character, but it adds an appropriate theme to the magic system.
As is typical for games of this area, your inventory limit is annoyingly small, especially since there's no way to get rid of plot items, even after they're no longer useful.
Side Quests/Optional Content: None of any consequence.
Interface: We still can't tell what the magic spells do without the instruction book, or know whether a piece of equipment in a shop is better than what you have equipped. At least this game has a general-purpose button so that you don't have to pick "talk" or "search" from a menu. The items and equipment are in a common pool (so that you don't have to transfer an item to another character before they can equip it). So once again, it has some of the annoyances of the era but overall not too bad.
Graphics/Sound: I would say both of these are average for the period. The graphics look very NES-ish, and the music is nothing especially memorable. One annoyance is the "heat shimmer" effect in the midgame, as well as the way the ground pixellates and shimmers when you're flying on Pegasus.
It sounds like what I'm saying overall is that this game is above average for its time, but wouldn't be near the top of best RPGs for the SNES. If you like the older Dragon Quest-style RPGs, it's a good play.