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