Full list of all 20 Angry Birds Stella achievements worth 200 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Windows Phone.
Earned 200 Stars
200 bounces with Stella
50 Three Starred Levels
Completed Episode 1
Used the Hammer Power-up ten times
Popped 1,000 Pigs
Earned 100 Stars
Played Game for One Hour
Earned 50 Stars
Get one bird to bounce on 5 drums in one level
Used the Hammer Power-up
Found 1 Photograph
Earn 300 Stars
Earn 5,000 Coins
Spend 5,000 Coins
Complete Episode 2
Find 30 Photographs
131 Three Starred Levels
1,000 bounces with Stella
Play Game for Ten Hours