Here is the full list of all 38 Souldiers achievements.
Defeat Iktala on Soldier or Warrior mode.
Destroy 3,000 environmental objects.
Destroy 10,000 environmental objects.
Discover 50 hidden rooms.
Find all of the hidden rooms.
Defeat Babylon on Soldier or Warrior mode.
Defeat Birk on Soldier or Warrior mode.
Defeat Project S on Soldier or Warrior mode.
Defeat Agginox on Soldier or Warrior mode.
Defeat all Dark Warriors.
Defeat Ratatosk on Soldier or Warrior mode.
Defeat the Minotaur
Defeat Brigard.
Defeat Sangrigor.
Defeat all Royal Scorpions.
Defeat Galath a second time.
Defeat 1,000 enemies.
Defeat 5,000 enemies.
Complete the game as a Scout.
Complete the game as an Archer.
Complete the game as a Caster.
Complete the game as all three classes.
Collect all orbs in the game.
Inflict altered states on your enemies 50 times.
Be revived by the Valkyries after falling in combat.
Unlock all skills.
Use 100 potions.
Complete all side quests.
Upgrade your weapon to the highest level.
Upgrade your protection the highest level.
Defeat 50 enemies using secondary weapons.
Collect all secondary weapons.
Collect all Dark Crystals.
Reveal 100% of every map.
Complete the Bestiary in your Encyclopaedia.
Complete the game on Warrior mode.
Finish a game on Game+ mode.
Defeat Beigon on Soldier or Warrior mode.