Here is the full list of all 23 Terraform achievements.
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
Start your 20th Terraform session
Start your 10th Terraform session
Play 100 turns of Terraform
Start your 5th Terraform session
Open the Level Editor
Use a total of 100 tools
Start your second Terraform session
Achieve a total Terraform rating of at least 100
Use a total of 10 tools
Retry a level
Play 10 turns of Terraform
Start your first Terraform session
Use a total of 1000 tools
Play 1000 turns of Terraform
Complete the University part of Terraform!
Complete the HexCorp part of Terraform!
Complete the Tellus part of Terraform!
Achieve a total Terraform rating of at least 500
Achieve a total Terraform rating of at least 1000
Achieve a total Terraform rating of at least 2000