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.
Find all the Journal Entries in the game.
Explore 100% of the map.
Unlock all the Bestiary entries.
Defeat a boss without getting hit.
Complete the game on Hard difficulty.
Defeat Ulak.
Break all the crates in the game.
Defeat the Shaman.
Find all the Powerups in the game.
Defeat 1,000 enemies.
Defeat King Trell.
Rescue all the missing villagers.
Become the Arena champion.
Defeat the Titan.
Defeat the Bone Worm.
Defeat the Wendigo.
Spend 5,000 gold.
Defeat 100 enemies.