Here is the full list of all 20 Chasm achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Defeat the Titan.
Defeat the Bone Worm.
Defeat the Wendigo.
Defeat 100 enemies.
Defeat 1,000 enemies.
Defeat King Trell.
Defeat the Shaman.
Defeat Ulak.
Spend 5,000 gold.
Find all the Journal Entries in the game.
Find all the Powerups in the game.
Break all the crates in the game.
Rescue all the missing villagers.
Complete all villager sidequests.
Explore 100% of the map.
Unlock all the Bestiary entries.
Defeat a boss without getting hit.
Complete the game on Hard difficulty.
Complete the game as a Mortal.
Become the Arena champion.