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