To obtain a score, you must finish the puzzle at least oncewith a number of moves below the limit (for more information on this, you can read the article In how many moves do I have to complete the puzzles?). The score is made of two things: the time you took to complete the puzzle, and a number of stars (1 to 3) which tells if your performance was good or brilliant.
An example of score: 3 stars obtained in 1 minute and 20 seconds
You can see your score at the end of a puzzle or on the map. When you play, your score automatically shows if you complete the puzzle within the time limit or if you reach the maximum number of moves. On the map, the puzzles you already completed have stars above them. Click on the number of a puzzle to show your score. The score displayed is your best score on this puzzle.
Here, the player obtained 3 stars at the puzzle 28, 1 star at the puzzle 29, and 2 stars at the puzzle 30
An example of score displayed at the end of a puzzle