Simple Sudoku Game

Simple Sudoku Game:

This simple sudoku game is aimed for kids (but not only).

You can play and have fun even if you can't read!

With a deliberately limited number of game options, everyone can understand how to play and how to adapt this game to his needs.

You can choose:
# difficulty: easy, medium, hard
# size: 2x2 (very easy, for kids), 3x2 (easy), 3x3 (standard)
# tiles theme: digits (standard), pictures (for kids, several themes available)

Some help can be provided with two buttons:
# "tip": will select next fillable cell on first tap, will fill this cell whith right value on second tap
# "conflicts": will show conflicting cells

Every grid has one unique solution. No assumption or guessing is needed to solve grids.