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