Here is the full list of all 20 Sundered achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Defeat Nyarlathotep.
Defeat Nyarlathotep & The Shining Trapezohedron.
Destroy seven Elder Shards.
Destroy your first Elder Shard.
Defeat Humanity.
Collect 500,000 Shards.
Find all Perks.
Corrupt seven Abilities.
Defeat Legion & Salvation.
Defeat all Minibosses.
Unlock all Abilities.
Equip three Perks simultaneously.
Defeat Hysteria.
Corrupt your first Ability.
Defeat Dominion.
Collect 10,000 Shards.
Equip your first Perk.
Survive your first horde.
Defeat your first Miniboss.
Unlock your first Ability.