Here is the full list of all 17 Flip Polygon achievements.
Complete a challenge
Complete Challenge 1-5
Complete Challenge 1-10
Complete the Challenge 1-15
Complete 25 Challenges
Complete 40 Challenges
Complete the Challenge 1-19
Complete the Challenge 2-13
Complete the Challenge 3-13
Complete the Challenge 4-13
Complete all challenges
Get 5 stars
Get three stars in one challenge
Get 10 stars
Get 50 stars
Get 100 stars
Get all the stars