Standalone add-on for Grandia on Saturn, I got sick of waiting for a potential translation for this so I went and played it anyway. Here are my thoughts.
There isn't much in the story department, Liete has built this museum and you have to help her fill it. There is a main hub area + 4 dungeons and you must clear those dungeons and collect key items in them to unlock more things in the hub area (brand new mini games, concept art, enemy list, save files for the main game at key points etc).
You start at lvl 22-24 and the party is Justin, Feena and Sue (you can't import your character data from the main game and you can't choose other characters, they're merely NPCs) and there is also a shop in the hub area. All the characters start with a lot of skills/spells learnt but still quite a few left to learn and master. At the start of the game you'll have to grind for at least 1 hour because you're not beating the boss of even the easiest dungeon in the starting state, I went to a harder dungeon to grind; then it should be smooth sailing and the balancing isn't too bad.
Dungeons from easiest to hardest seem to go: Ruins -> Military Base -> that scaffolding area -> Tower; although Military Base and the scaffolding area are sort of tied and Military Base might have harder bosses, it offers more save points and the ability to backtrack while the scaffolding area can be a death trap if you're not prepared. Liete recommends to go to the scaffolding area first but that's bullshit unless she meant to go there only to grind before coming back later.
The dungeons are okay, some puzzles to solve, secrets to find protip: there are a couple of weapons hidden at the start of the Ruins area; but nothing ground breaking either. I'm pretty sure all the enemies are from the main game though some might have inflated stats but some areas graphics are new.