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