Here is the full list of all 20 Heart of Moon : The Mask of Seasons achievements.
Reach the high score (7 steps)
Break as many chains as you can (7 steps)
Help the inhabitants of the island (7 steps)
Trigger as many traps as possible (7 steps)
Explode as many rocks as you can (7 steps)
Become rich! (7 steps)
Trigger as many darts as possible (7 steps)
Get the stars! (7 steps)
Gather resources during your trip (7 steps)
Kill many bosses in fight mode (7 steps)
Finish the game!
Win the second fight against 'Giant-Crab'
Win the second fight against 'Spider'
Win the second fight against 'Thief'
Win the second fight against 'Wolf'
Win the second fight against 'Djiin'
Finish a level in less than 30 seconds
Repair the pirate boat
Reach level 100
Complete the first 'Spot the difference'