Here is the full list of all 20 Chasm achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Unlock all the Bestiary entries.
Complete the game as a Mortal.
Complete all villager sidequests.
Find all the Journal Entries in the game.
Explore 100% of the map.
Break all the crates in the game.
Defeat Ulak.
Rescue all the missing villagers.
Complete the game on Hard difficulty.
Defeat the Shaman.
Find all the Powerups in the game.
Become the Arena champion.
Defeat King Trell.
Defeat the Titan.
Spend 5,000 gold.
Defeat the Bone Worm.
Defeat the Wendigo.
Defeat a boss without getting hit.
Defeat 1,000 enemies.
Defeat 100 enemies.