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