
That is a hard boss! I loved I am Setsuna, but one problem I did have is it felt the bosses were a bit unbalanced compared to the other enemies you fight. Luckily you shouldn't have too much trouble with the rest of the game, except maybe the final boss, depending on what level you're at.
Hopefully their next game, Lost Sphear, will be even beter. I played it at PAX West. Check out my blog for more info. --Cary