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
Find the red Snalien
Complete all levels on the South Pole
Find the blue Snalien
Complete all levels on the Red Forest
Find the green Snalien