I found the difficulty to be largely on point in all fairness.
The beauty about RPG type games is that you essentially let the player set their own difficulty to a degree. If it's too hard, you can grind until you don't get smashed by everything or too easy and you can just breeze through until the next difficulty spike.
For instance, I completed with Henry Lv28 because I like to grind quite a lot (but not as much as some people). Other folk may want to speedrun the game and beat the final boss with a Lv16 Henry or something.
Oh yeah - I had to look it up but the ending song was 'Cradle of Forest' :)