I was level 17, and I did it without the berries, 'cause I didn't know they existed. I also beat it at my first try, but with only two characters alive in the end. I had Penelo and Fran with Bows, and casted some magic with the others. Basically, I used everyone but Penelo and Fran as human punchingbags for Garuda so Penelo and Fran could attack undisturbed.