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