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.
Die 2500 times
101% the game
Rescue all the sea critters
Rescue Cactus, Holly, Lemon, and Coral from Assault Android Cactus
Beat the Octosphere
Beat a level with Red
Rescue 100 sea critters
Beat The Fall of Gravity
Beat the game in under 60 minutes!
Die 500 times
Rescue Snakebird from Snakebird
Unlock the final zone
Rescue the Shopkeeper from Crypt of the Necrodancer
Collect all the timed orbs
Beat a level with Green
Rescue 50 sea critters
Rescue Guac from Burrito Galaxy
Beat a level with Blue
Die 100 times
Rescue Fish from Nuclear Throne
Find a hidden level
Beat a level with Purple
Unlock a Containment Level