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