Here is the full list of all 32 Gravity Den achievements.
Die ten thousand times!
Scare away 1000 crows!
Collect all stars in the hardcore zone #5!
Complete all hardcore levels!!!
Complete all levels in Hardcore Zone #5!
Collect all stars in the hardcore levels!!!
Scare away 250 crows!
Die a thousand times!
Open the About window
Complete all levels in Hardcore Zone #4!
Collect all stars in the hardcore zone #4!
Collect all stars in the hardcore zone #3!
Complete all levels in Hardcore Zone #3!
Complete 10 hardcore levels using only gravity shift!
Complete all levels in Hardcore Zone #2!
Collect all stars in the hardcore zone #2!
Complete 5 hardcore levels using only gravity shift!
Collect all stars in the hardcore zone #1!
Complete all levels in Hardcore Zone #1!
Collect 100 stars!!!
Complete hardcore level using only gravity shift!
Collect all stars in the normal levels!!!
Complete all normal levels!!!
Die a hundred times!
Complete 20 levels using only gravity shift!
Collect 50 stars
Complete 10 levels using only gravity shift!
Complete level using only gravity shift!
Collect 10 stars!
Die a ten times!
Die once!
Scare away a raven!