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