wow when i first played this game... that's going back too far for me to remember

Obviously omega and shinryu took me a few tries each to figure out, other than that i don't think anything gave me that much trouble.

But there are tonnes of memorable bosses in this game. I loved dividing your party to take on Minatauras and Omniscient, one of which was a physical attacks only boss while the other is magic only. Any fight with Gilgamesh was also memorable.

To keep on topic (sort of) During my solo character, no mixing job classes challenge, i found Gil Turtle to be one of the most challenging battles.