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.
Reached level 99!
Cleared all 73 dungeons!
Completed all 67 side quests!
Completed the Main Quest!
Obtained all 12 spells!
Obtained all 101 equipment!
Entered the new continent!
Completed the first quest!
Unlocked 3 Royal Arts!