There are background music and sound effects.
You can switch off them by tapping their buttons.
The buttons are at top left and top right corners.
For top wide button, it moves to an upper menu.
You can go back and select another game mode.
For bottom wide button, it is for Purchase Hints.
There are 4 game modes, namely
FREE, EASY, HARD and CRAZY.
Each of them contains 25 levels.
FREE mode is open for all players.
EASY, HARD and CRAZY modes are paid to unlock.
The game rule is quite simple, just tap a face.
The face will be toggled between sad and happy.
The faces on the top, bottom, left and right
of the face you tap will be toggled also.
Your target is turning all faces to happy
in the fewest moves so as to pass a level.
If you are in a mess to pass the current level,
you can tap RESET button at left bottom corner.
If your moves are over 999, it will auto RESET.
If your moves are the same or fewer than mine,
you will get a STAR as a badge for this level.
Challenge my records and try to get all badges.
You are given 5 free hints in the whole game,
you can tap HINTS button at right bottom corner.
After tapped, some faces are enclosed by frames.
You tap them all once so as to pass this level.
You can only buy hints after Unlock Modes.
Get 1 HINT for every 5 stars in the same Mode.