You will have to complete three slide puzzles each with increasing difficulty.
Once you solve one puzzle, you will confront the next one.
Each puzzle gets progressivly harder with the size increasing from 3x3, 4x4, etc.
You will have a total of 600 seconds (or 10 minutes) to complete all puzzles.
If you complete the 5x5 puzzle with at least 200 seconds left to spare (3 minutes and 20 seconds),
a secret puzzle will open. Complete the secret 7x7 puzzle before the timer is up, and
you will get the secret ending!!!