Here is the full list of all 23 Airscape - The Fall of Gravity achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
101% the game
Beat the game in under 60 minutes!
Beat The Fall of Gravity
Collect all the timed orbs
Rescue all the sea critters
Rescue Snakebird from Snakebird
Rescue Guac from Burrito Galaxy
Rescue the Shopkeeper from Crypt of the Necrodancer
Rescue Cactus, Holly, Lemon, and Coral from Assault Android Cactus
Beat the Octosphere
Unlock the final zone
Rescue 100 sea critters
Beat a level with Red
Beat a level with Green
Beat a level with Blue
Rescue 50 sea critters
Rescue Fish from Nuclear Throne
Find a hidden level
Beat a level with Purple
Unlock a Containment Level
Die 2500 times
Die 500 times
Die 100 times