Here is the full list of all 19 Unravel Cyndy achievements.
You have solved half of the puzzles.
You have completed "A night to remember" story
You have completed "Alex meets Cyndy" story
You have completed "Anne and Cyndy at the pool" story
You have completed a 6X6 puzzle
You have completed the "Cleaning Call" story
You have completed a 8X8 puzzle.
You can completed the "Fun in the sun" story
You have completed the "Her first porn" story
You have completed the "Lila's basement" story
You have completed a 10X10 puzzle
You have completed a 4X4 puzzle
You have completed all puzzles using HINTs for some of them or all of them
You have completed the "Slammed up" story
You have completed the "Wake up surprise" story
You have completed a 6X6 puzzle with a HINT penalty lower than 20
You have completed a 8X8 puzzle, with a HINT penalty lower than 30
You have completed a 10X10 puzzle, with a HINT penalty lower than 40
You have completed the game with a perfect score. All puzzles were solved and no hints were used. You need 4410 points for this achievement.