Here is the full list of all 9 Cat Quest II achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Cleared all 73 dungeons!
Completed all 67 side quests!
Obtained all 12 spells!
Obtained all 101 equipment!
Completed the Main Quest!
Reached level 99!
Unlocked 3 Royal Arts!
Entered the new continent!
Completed the first quest!