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