There's three very good reasons this is one of the finest JRPGs ever. The first is the absolutely top notch visually and audibly, it has an incredible style, some of the finest SNES sprite-work ever made (off the top of my head it's only competition is Rockman & Forte and maybe Chrono Trigger), a killer soundtrack, and an astonishing amount of variety in locations, environments, and enemies (this is literally the largest SNES game measured by kilobytes); you'll have been to more unique locations when the game is 1/3 over than lesser JRPGs will do in their entire adventure. The second reason is the game's sense of adventure; the world feels big, the antagonist's mischief is clearly in the world, and all the little sub-plots relate back to the mainstory or explore something important about the world, rather than feeling like a series of one-shots. And third, and this is the real reason to play the game in current year when there's so many other options: multiplayer. To my knowledge the number of JRPGs that have this feature is pitifully small, and the few that existo lack many features and conveniences SD3 has (the Tales of Games for instance only allow the other player to exist during battles. He can't run around the world with you). With rom hacks the game supports 3 people, 2 players on a standard rom.
By today's standards, the game's combat and character development is shallow, you can make a party of 6 from 3 characters, assign each one of 2 classes, and than 2 further sub-classes, and slightly tweak their stat points. There's only a single, basic attack per character and your ability to avoid enemy attacks consists of only a slow back-peddle; this isn't Ys where a skilled player dances around the enemies never getting touched, although good foot-work will preserve plenty of hit points, as well being mindful of triggering spell-counters. There is however an impressive collection of spells and special abilities- all of which slow down the action by pausing while a spell animation plays (although if you don't elect to have Angela, the pure caster, in the party this is not much of a nusance. Never bring her to a co-op game, you'll annoy your friends with your spell spamming).
However this shallowness is largely made up for by the game being extremely well paced. You don't go through dozens of identical rooms, have intros/outros to every fight, micro-manage some tedious bloated menu/item horde (the plague of modern JRPGs). Even movement out of combat and transportation between land masses is very fast, taking you straight to whatever point of interest you want. You rarely feel like you need to grind, and when you do it's over fast (minus the optional grind to get the legendary equipment in the final dungeon). Past the game's lengthy intro, cutscenes never go on for so long you get bored nor are they so infrequent that it feels like there isn't a narrative to your adventure. Even our story is paced well with it being relativily free of filler, clear advancements in the characters goals happening regularly, and a gradual reveal of new characters and plot-twists with the story gradually turning from being about the character's own personal goal to them becoming the destined hero that saves the world.
There's a few rough points like buggy spells/items that don't have their full power (the only truely crippling one being that the luck stat gives almost no critical hit bonus at all, making it useless outside of avoiding a few trapped chests). And of course like all JRPGs it's incredibly easy due to the how your ability to heal the party only goes up and up as the game goes on.
But given that it is free of so many of the annoying parts of JRPGs, is arguably the best looking 2D one ever made, and has 3 player multiplayer, if you like JRPGs at all this is a must play.
