Here is the full list of all 44 Trials of Mana achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Obtain all achievements.
Defeat Mondoragon.
Learn all abilities as any character.
Become a master guard.
Become a master swordsman.
Become a master cleric.
Play with all six main characters.
Complete Duran's story.
Complete Charlotte's story.
Complete Riesz's story.
Defeat Dark Lich.
Learn 20 abilities as any character.
Purchase nitromyte for the listed price.
Defeat Anise on hard.
Stop the end of the world.
Defeat Black Rabite.
Accumulate at least 500,000 lucre.
Become a master thief.
Become a master fighter.
Become a master magician.
Complete Angela's story.
Complete Kevin's story.
Complete Hawkeye's story.
Complete Chapter 6.
Defeat Archdemon.
Find Li'l Cactus in all possible areas.
Max out magic pot level.
Accumulate at least 100,000 lucre.
Open 200 treasure boxes.
Complete Chapter 5.
Complete Chapter 4.
First ride on Flammie.
Complete Chapter 3.
Open 100 treasure boxes.
Complete Chapter 2.
First ride on Vuscav.
First class switch.
Complete Chapter 1.
First cannon ride.
First encounter with Li'l Cactus.
First time learning a chain ability from an unexpected acquaintance.
First time learning a companion's chain ability.
First time planting a seed.
First time learning an ability.