Here is the full list of all 40 The Vagrant achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Unlock all achievements
Achieve true ending
Clear the game in Hard difficulty
Collect 1000000 mana
Acquire Sword of verum
Unlock all entries in Monsterpedia
Acquire all skills
Unlock all abilities
Collect 1000000 gold
Defeat Fallen Kumasith
Explore all areas
Acquire a weapon or armour with 4 runestones
Acquire all recipes
Failed to defeat Santiago
Failed to defeat Kumasith
Defeat Soulreaper
Consumed 100 potions in total
Achieve normal ending
Unlock all entries in Note
Acquire an onion from the chef in Brocley village
Defeat Valerie
Failed to defeat Shroom prime
Defeat Shroom prime
Defeat Ground shaker
Stop Soulreaper
Slay the chicken
Failed to stop Soulreaper
Achieve 999 combos
Achieve 500 combos
Achieve 100 combos
Defeat Santiago
Slay 666 monsters
Defeat Headless horseman
Defeat Kumasith
Defeat Maximillian II
Defeat HMWV
Acquire a max ranked weapon or armour
Defeat Esgonian general
Fight Soulreaper
Keep drinking potions