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