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