First of all thanks for rating my OST, it means a lot!
I have watched the Youtube Video and it was a very nice experience. The Text combined with the music was very powerful and really immerses one in the story.
It was a very nice arrangement and the Choirs were amazing. It all had a similar vibe, wjcih added to the story building, really characterizing Thalasia.
I think as a game OST it would need to be a bit more loopable, but that would probably work if the remainder was just cut.
Overall it was still a very nice OST, that really fit the character you described, keep it up :D