Here is the full list of all 43 Chronos: Before the Ashes achievements.
Complete the Game on HEROIC
Complete the Game on any Difficulty
Complete the Game on ADVENTURE
Defeat the Dreamer
Put 30 Attribute Points into Arcane
Defeat the Labyrinth Guardian
Acquire the Labyrinth Scythe
Exchange your Starting Weapon with a Krell Version
Return a Keepsake to the Krell King
Acquire the Shadow Stone
Travel to Ward 16 by Way of the Mirror
Defeat the Pan Guardian
Acquire the Pan Shield
Put 30 Attribute Points into Vitality
Upgrade Any Weapon to Level +5
Put 30 Attribute Points into Strength
Defeat the Red Widow
Read 10 Books or Scrolls
Solve the Flautist Riddles
Meet the Pan Flautist
Acquire the Pan Spear
Acquire the Lightning Stone
Create a Rare Dragon Shard
Open a Dragon Inscribed Box
Craft a Krell Mace
Defeat the Stone Golem
Defeat the Krell Guardian
Acquire the Krell Hidden Weapon
Acquire the Krell Shield
Acquire the Sun Stone
Upgrade Any Weapon
Read 5 Books or Scrolls
Acquire the Krell Hammer
Put 30 Attribute Points into Agility
Acquire the Fire Stone
Meet the Krell Blacksmith
Unlock Your First Trait
Acquire a Dragon Heart
Complete the Game at age 21 or younger
Unlock Everything
Upgrade Any Weapon to Level 9
Complete the Game in NG+ Mode