Here is the full list of all 16 HelpTheAlien achievements.
clear stages 1
clear stages 10
clear stages 25
clear stages 50
perfect clear stages 1
perfect clear stages 10
perfect clear stages 25
perfect clear stages 50
total coin 10
total coin 100
total coin 1000
total coin 10000
total hats 1
total hats 10
total hats 20
total hats 27