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