Here is the full list of all 11 Celia's Quest achievements.
Learned and upgraded all Brawl skills!
Learned and upgraded all Tech skills!
Learned and upgraded all Magic skills!
Learned and upgraded all Swashbucklery skills!
Learned and upgraded all Spellbladery skills!
Learned and upgraded all Techmathurgy skills!
Reach the bad end. Oh no...
Reach the neutral end. Oh well.
Reach the good end. Good job.
Reach the true end. Woohoo!
Finish the game on Hardcore, New Game Plus, and reach the true end!