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