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