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