Here is the full list of all 50 Foregone achievements.
Collect all Trophies
Acquire all Skill Upgrades
Max all possible nodes in Skill Mastery
Discover all secret locations
Defeat an elite enemy inside Bastion
Kill 10 enemies before Barrier's duration runs out
Hit 6 enemies with one Raze
Kill 5 enemies with a single use of Overdrive
Discover all secret locations in a level
Kill Project Zeus
Spare Project Zeus
Defeat Project Zeus
Acquire all Diary Pages
Acquire all collectibles
Defeat the revived Project Poseidon
Acquire all Military Reports
Max all possible nodes in the Skill Tree
Defeat the revived Project Demeter
Acquire all Lab Notes
Equip a Mythic item in each active slot
Defeat the revived Project Hera
Acquire all Commander's Logs
Ascend to a secret location with Wall Climb
Discover the Warden's plan
Acquire all Abilities
Defeat Project Poseidon
Learn the truth of the Arbiters
Acquire all Catalysts
Acquire all Skills
Upgrade a Mythic item to Level 5
Defeat the King of Calagan
Uncover a secret location with Ground Smash
Complete a branch in Skill Mastery
Defeat Project Demeter
Defeat Tecton
Acquire a Skill Upgrade
Reminisce at the Courtyard
Defeat Project Hera
Complete a branch in the Skill Tree
Speak to the Ferryman
Damage 8 enemies with one Nova
Destroy the Buzzbot
Damage 4 enemies with one Surge
Acquire a Catalyst
Heal with Restoration in mid-combat
Discover a secret location
Acquire a collectible
Upgrade an item
Allocate Essence into the Skill Tree
Complete the Prologue