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