Here is the full list of all 11 Snaliens achievements.
Find what caused the spaceship malfunction
Complete all levels on the North Pole
Complete the last level
Solve the level with all Snaliens
Complete all levels on the Desert
Complete all levels on the Forest
Complete all levels on the South Pole
Complete all levels on the Red Forest
Find the blue Snalien
Find the red Snalien
Find the green Snalien