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