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