Here is the full list of all 15 Flip That Coin! achievements.
Unlocked Chest Coins!
Achieve 3 stars in random mode
Achieve 3 stars in basic mode
Achieve 3 stars in small mode
Unlocked Diamond Coin
Achieve 3 stars in big mode
Achieve 3 stars in tripple mode
Unlocked Strawberry Coins!
Achieve 3 stars in double mode
Unlocked Pixel Coin!
Achieve 3 stars in normal mode
Unlocked Star Coins!
Unlocked Sun Coins!
Unlocked Bag Coins!
Unlocked Crystal Coins!