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