Here is the full list of all 24 The Ambassador: Fractured Timelines achievements.
Defeat an elite enemy
Defeat Caor
Defeat a Treant
Defeat Fergus
Defeat a Golem
Defeat the High Priestess
Defeat a Bulger
Defeat Balor
Defeat the Lord of Time
Complete every level without taking damage
Complete every level without eating
Find all twenty collectibles
Destroy every barrel in the game
Complete the time trial for every level
Talk to every NPC in the game
Kill three enemies with one shot from the Buster Wand
Freeze six enemies at once using Coldhart
Kill three enemies with flaming corpses left behind by Flametongue in a single level
Kill five enemies with a death block in one level
Kill 20 enemies in 20 seconds
Kill an enemy in their invulnerable state
Find the golden dino!
Beat 10 waves in Blood Henge
Complete the campaign on naked mode