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