Here is the full list of all 15 Double Trouble achievements.
Collect 10 pieces of fruit
Build up 10 town tiles
Deliver your first animal to a farm
Collect 100 pieces of fruit
Collect 1000 pieces of fruit
Deliver 10 animals
Deliver 100 animals
Delivered a unicorn
Build up 100 town tiles
Build up 1000 town tiles
Fly an airplane
Fly 10 airplanes
Launch a rocket
Launch 10 rockets
Visit 10 observation posts