Secret of Evermore actually uses a completely different engine than Mana. The developers basically tried to mimic it, but they didn't use any of the original code. It's probably still feasible to do though.
Maybe not be as well known as I thought, Evermore was the first game by an American team Square hired.
They reported that some changes in the game, such as being one player only, was due to the game being originally intended for half the ROM size it released on.
Might have been the only released game as well. I think they had one or two other games announced in a very preliminary stage, including an official Evermore sequel, before the first game was even out.
But then a year later the PlayStation "war" happened and Square reportedly replaced their US subsidiary entirely.