Keep in mind I really didn't go out of my way to find side quests. There was a puzzle in the final dungon that I didn't even do and it let me go to then end of the game. I also didn't master all of the abilities and I was not even at level 60 when I beat the game(I spent 0 hours leveling up the whole game...and I avoided a lot of battles or ran away). I am sure if I did more that it would be longer by at least another 10 hours.