Glacier Blast

These achievements require that you earn a cumulative total of 20 stars in Puzzle Mode. Each level you can earn up to three stars. Scoring more points will earn you more stars. Each breaker (the predefined shapes at the bottom of the screen you drag up onto the board) is made up of four tiles that you match with the tiles on the board to destroy. 10 points are earned for each block destroyed, and the number of blocks you destroy per breaker is used as a multiplier. Since the number of blocks on the board is fixed, the real goal in the game is trying to combine breakers efficiently to consistently earn the largest multipliers. 1 star can be earned just by completing the level, but two and three stars is where strategy plays in.

You will have no trouble earning 20 stars. There are 50 levels in the game spread across 5 worlds, offering a total of 150 stars. Subsequent worlds and levels are unlocked by meeting star requirements. See these requirements in the level-selection screen.

NOTE: The "Sapere Aude!" achievement is most easily done on World 5, Level 3, which requires 74 stars to unlock. See that specific achievement for more info.