Grandia II is a classic, Grandia I is a formative game for its series, Grandia III...almost happened.
But Xtreme? It's in a class all its own. It IS finished, because it focused not on the story, or the characters, though it has a bit of each. No, this entry was laser focused on that battle system, which even to this day, is semi-unique to the series. And here, it's polished to a mirror shine, as every character has special moves, combinations of characters make them stronger, and magic can be learned and used by anyone.
Even better, it expanded the AI system of the first two entries. Now not only at the enemies smart enough to take advantage of the battle gauge in a way only bosses did before, but your party does the same even when you set them to auto, making for an all around smooth experience for grinding, which you will be doing a lot.
All in all, this won't win awards for writing, swears like Shadow the Hedgehog, and has a cliche as I'll get plot. But that battle system kept me going through the bonus dungeon, and fighting the final super boss, just to see what I could get...I do hope if they can get it we get a fast forward button, mind. Some of the animations in combat take a while.