Here is the full list of all 15 Xanadu Next achievements.
Found and translated all tabulae and memoirs.
Mapped 100% of the game.
Innately learned all skills and acquired all levels of all spells.
Defeated Galsis.
Found and maxed out all Guardians.
Defeated Lorelei.
Defeated Ascomoid.
Defeated Evilwurm.
Defeated Scoltula.
Barely made it back to shore after almost drowning.
Defeated Dvorak.
Defeated Berilard.
Reached max rank.
Conquered another dimension.
Attained all other achievements.