Grandia II, like most Japanese console RPGs. is basically a REALLY long morality play (in this case about 30 hours if you plow through it, maybe less if you're ambitious) broken up by strategic combat sequences.
Every aspect has to be viewed for its own sake, because in this type of game, what is inconsequential for one gamer may be make-or-break for another.
The game's story, though moving, has certainly been done before in other games, and later games will borrow from this story. However, how well does it tell its story of Light, Darkness, and... in between? Fairly well. The translations aren't broken in any sense, although there is some unnecessary meandering for the sake of the story (yes, we know he's evil, so kill him already). There appears to have been minor edits for the sake of toning down incursions against religion, nothing that changes the essence; rather, it just gives it a less inflammatory feel.
Protagonist characters include the usual cast: your swaggering, swash-bucking selfish youth, the naïve "she'd be hot if she weren't so stuck-up" waif, the evil demon-spawn who may not be evil, just misunderstood, the man-child who can command the elements, but can't yet grow pubic hair, the artificially created life form who says poignant things, and the Really Big Ugly Guy who can be surprisingly soft-spoken.
I played on the PC port, so graphically, the game is superior to any other J-RPG type of release for that platform. I never felt compelled to crank up the anti-aliasing in my 3-D card, as I did with FFVII & VIIII.
Sound is… iffy. Sound effects were adequate, if a little too "cartoony". There was just some weird white noise in the background of the spoken dialog that drove me nuts. Music was mixed. You won't find any orchestrated pieces, but you will find the most teak-jerking vocals (Portuguese a capella) this side of FFVIII. Some of the other stuff just doesn't feel like it fits in, until the end of the game, when it actually seems logical. Just trust me on this one.
The game mechanics themselves are things we've seen before: kill monsters, get gold and experience, use the gold to buy more stuff, kill the foozle at the end, etc. However, you don't just get experience for your characters. You also get Special Coins, which can be spent on various high-power Moves for each individual character. These coins can also be invested in reading Skill Books, whose pages can be equipped by the characters to give bonuses, ranging from the mundane yet powerful (extra hit points) to the esoteric (make yourself more likely to be attacked, for use with the counter-attack skill). Additionally, you get magic coins, which can be used to power up spells which are contained in various Eggs (think Materia, only really, really powerful) you find throughout the game.
The absolute best reason for this game's existence is the Battle System. Characters fight in a 3-D expanse. Each fighter progresses along a bar at their own speed, and as each one reaches a point, they have a choice as to what to do. It's not committed to immediately though. Different actions have different charges (a straightforward attack charges immediately, while a special Move which has had little investment will take a long time to charge. This final charge time gives opponents a chance to Cancel a move, interrupting it and sending that character down the action bar. Also, at the moment of attack, a faster attacker can charge in and cause a Counter, worth bonus damage, but at the risk of being Countered himself. The description really doesn't do it justice. It's important to note that experienced gamers will have little trouble with this game unless they habitually skip battles, fail to wear equipment, etc. It's a very well-done system, but the fighting just is not at a high degree of difficulty.
A final caveat: This game's length isn't "30 hours unless you want to find all of the secrets." It's 30 hours. It's a very linear game, almost as much as Mystic Quest.
Basically, if you want to purchase a Japanese RPG without "Final" in its title, this is a solid one to buy. It puts together a complete package, at a difficulty that won't turn off newcomers, with just enough new elements to make it worth your time.