The introductory chapters are all pretty easy, but they are less than the first half of the game. It gets more difficult once you hit the real meat of the game (for example you fight no real bosses until chapter 5). I have had some intense boss fights where I have to cast heal twice per round as well as stack buffs/debuffs and even then I win by the seat of my pants.
i dunno i'm 30 hours in and abominable showman was STILL my hardest boss. it's not really difficult but i had terrible
terrible luck fighting him.
for that those that don't know, he creates three duplicates of himself and you have to strike the right one. to make matters worse, you fight him with one character. he's not strong but his duplicates are completely random. sometimes there would be a pattern where he'd attack from the same spot 5-6 times in a row but sure enough when you target that enemy he ends up in another one.
i just targeted a single clone and prayed i hit the right one. 5 tries later (the guy and all the battles before seriously took up all of my healing items) i finally killed him.