Verndragonx

It's fairly difficult in the early game, depending on how much you level up. Beating Lich one on one is tough no matter what, Astos can be more annoying than tough since he loves to use the Rub spell, and the Vampire can paralyze you and kill you without getting a turn. But once you get the canoe the game opens up for you to get some of the better weapons and fight things that are worth more and aren't so tough
With a little time it can be fun. It makes some of the more simple parts of the game tougher, anything thing that paralyzes you can make for a long fight. I had to go through the last part of the game numerous times before I finally beat Chaos, but I think it was worth it. I know some don't like the idea of using less than the full group, but for those who love the game it offers a different angle to try out. I am currently playing the game with a thief and a white mage, and it's fun and so far even more frustrating than the one fighter. Give it a try, if you like the game and know the in's and out's to help yourself it's a fun challenge.