Well, things have changed in these months.
It turns out that the game uses a "rare" Korean encoding, although Mantra used its own encoding on top of this one, but it's easy to map. (CP1361 or Johab encoding, none of my hex editors support it, except IDA Pro)
So, basically, the script seems to have been dumped properly, and can be reinserted as well.
There's a Korean translator this time. (The script is 45k characters long).
I still have to figure out the image format, since the opening "text" are images.
The game script format is more similar to a modern Ys/Kiseki script than something like Brandish 2, which was pure ASM. It's got 144 different opcodes.