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.
Defeat Archdemon.
Learn all abilities as any character.
Become a master magician.
Become a master guard.
Become a master fighter.
Play with all six main characters.
Complete Angela's story.
Complete Kevin's story.
Complete Riesz's story.
Defeat Dark Lich.
Learn 20 abilities as any character.
Obtain all achievements.
Purchase nitromyte for the listed price.
Accumulate at least 500,000 lucre.
Stop the end of the world.
Defeat Anise on hard.
Max out magic pot level.
Become a master thief.
Become a master cleric.
Become a master swordsman.
Complete Duran's story.
Complete Charlotte's story.
Complete Hawkeye'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 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.