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