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