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