Here is the full list of all 29 Creeper World 4 achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
1st Hold Objective
Activate easter egg in 'Before Time'
Activate easter egg in 2nd story mission
Completed all story missions
Story Mission 20 Complete
Story Mission 19 Complete
Story Mission 18 Complete
Activate easter egg in 1st story mission
Story Mission 17 Complete
Story Mission 16 Complete
Story Mission 15 Complete
Story Mission 14 Complete
Story Mission 13 Complete
Story Mission 12 Complete
Story Mission 11 Complete
Story Mission 10 Complete
Story Mission 9 Complete
Story Mission 8 Complete
Story Mission 7 Complete
1st Reclaim Objective
Story Mission 1 Complete
Story Mission 2 Complete
Story Mission 3 Complete
Story Mission 4 Complete
Story Mission 5 Complete
Story Mission 6 Complete
1st Totem Objective
1st Collect Objective
1st Nullification Objective