I've finished the optional boss fight and made sure the optional ending looked good, then I moved on to optional boss refights and decided to work on the higher level of skills you could get at that point; Doing so, I decided to add all skill levels already so they'll be there when I get at the appropriate level! Tomorrow I'll keep on working on the skill levels, then the boss refights, then move on with the story.
Time spent on the project so far: 672 hours
Currently working on: Skill levels + optional boss refights