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