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