Here is the full list of all 20 Sundered achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Equip three Perks simultaneously.
Defeat all Minibosses.
Corrupt your first Ability.
Unlock all Abilities.
Defeat Hysteria.
Defeat Dominion.
Destroy your first Elder Shard.
Collect 10,000 Shards.
Survive your first horde.
Unlock your first Ability.
Defeat your first Miniboss.
Equip your first Perk.
Destroy seven Elder Shards.
Corrupt seven Abilities.
Find all Perks.
Defeat Legion & Salvation.
Defeat Nyarlathotep.
Defeat Nyarlathotep & The Shining Trapezohedron.
Defeat Humanity.
Collect 500,000 Shards.