Here is the full list of all 23 Terraform achievements.
Achieve a total Terraform rating of at least 2000
Complete the Tellus part of Terraform!
Start your 20th Terraform session
Achieve a total Terraform rating of at least 1000
Complete the HexCorp part of Terraform!
Start your 10th Terraform session
Play 1000 turns of Terraform
Share ten planets made with the planet editor on Steam Workshop
Share five planets made with the planet editor on Steam Workshop
Share one planet made with the planet editor
Open the Level Editor
Use a total of 1000 tools
Achieve a total Terraform rating of at least 500
Start your 5th Terraform session
Complete the University part of Terraform!
Start your second Terraform session
Start your first Terraform session
Play 100 turns of Terraform
Use a total of 100 tools
Achieve a total Terraform rating of at least 100
Retry a level
Use a total of 10 tools
Play 10 turns of Terraform