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