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