Here is the full list of all 40 Lost Ruins achievements.
Defeat 47 enemies with a Gladius.
Arrive at the one true ending.
Collect every artifact.
Complete Assassin Mode.
Defeat every boss.
Defeat 60 bugs.
Defeat 50 enemies with ice spells.
Visit every area.
Defeat 10 Banshees.
Hear all of the Goblin Merchant's tales.
Complete Witch Mode.
Defeat 20 enemies with a Holy Sword.
Collect every piece of equipment.
Destroy 5 icons.
Defeat 66 Demon or Undead enemies.
Collect every record.
Defeat 30 Plant monsters.
Inflict 50 critical hits with a Bow.
Consume 100 Meat items.
Earn 999 gold.
Defeat 44 enemies with Corpse Absorption spells.
Block 50 Attacks.
Defeat 5 Orcs.
Defeat 50 enemies with Fire spells.
Discover another ending.
Defeat 50 enemies with a Sledgehammer.
Defeat 30 enemies with Runic spells.
Land 50 attacks on enemies by penetrating their shields.
Inflict 30 critical hits with Throwing weapons.
Collect every Spell.
Deflect 20 enemy attacks with a Katana.
Arrive at the end.
Defeat Sadora the Ascetic.
Defeat 20 enemies by using traps.
Open every treasure chest.
Complete every quest.
Collect every weapon.
Unlock every art piece.
Complete Hardcore Mode.
Complete Boss Mode.