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.
Defeat Humanity.
Collect 500,000 Shards.
Corrupt seven Abilities.
Corrupt your first Ability.
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.
Defeat your first Miniboss.
Equip your first Perk.
Survive your first horde.
Unlock your first Ability.