Here is the full list of all 30 Downward achievements.
Get 10 Gold medals in the Challenges.
Perform 500 wall-runs.
Obtain 2000 Skypieces.
Perform 500 slingshots.
Get a Gold medal in the Challenges.
Perform 500 double jumps.
Perform 500 wall-jumps.
Unlock all Wisdom skills.
Obtain 1000 Skypieces.
Survive your own recklessness.
Unlock all Meditation skills.
Unlock all Pursuance skills.
Unlock all Insight skills.
Buy all the upgrades of the Old Man's Room.
Build four different rooms in the Merchant's Lair.
Unlock all Endurance skills.
Die from a Cactus.
Sell 15 items to the Merchant.
Obtain the Slingshot Artifact.
Reach the temple on top of the cliff.
Gather 50 Dry Artifacts.
Obtain 500 Skypieces.
Gather 25 Dry Artifacts.
Sell 5 items to the Merchant.
Die from a Drone explosion.
Obtain the Double Jump Artifact.
Exit the tutorial area.
Defeat your first golem.
Use the Mark for the first time.
Wake Up!