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 & The Shining Trapezohedron.
Destroy seven Elder Shards.
Destroy your first Elder Shard.
Defeat Humanity.
Corrupt seven Abilities.
Defeat Nyarlathotep.
Corrupt your first Ability.
Defeat Legion & Salvation.
Find all Perks.
Defeat all Minibosses.
Collect 500,000 Shards.
Unlock all Abilities.
Equip three Perks simultaneously.
Defeat Hysteria.
Defeat Dominion.
Collect 10,000 Shards.
Equip your first Perk.
Defeat your first Miniboss.
Survive your first horde.
Unlock your first Ability.