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