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