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