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