Sudoku Electronic Game

Function descriptions:
1) Three modes: easy, medium, hard
2) Every mode can Automatically generate many puzzles
3) With memory function which can record the rate of game and the highest 
    grades, LED backlight, intelligent control (manual or automatic, optional) 
4) "Sleep" function: automatically enter into "sleep" state when the off-work 
     time is up to 10min, when you turn on the game next time it would continue
     to work
5) Automatic answer: press "submit" to examine the answer when finished 
    game along with displaying right or wrong, and corresponding sound as
     well
6) Touch design: big screen LCD display, suitable for using at day and night
     (need to turn on the LED backlight)
7) Key sound hint, different key uses different sound hint function and can
    prevent mistake from operation