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