It looks like your typical sudoku game - nice graphics - follows the KISS (keep it simple) method of design.
I would add (unless I missed the feature) a way to (whats it called?) "mark" the numbers I think it might be like...
+----+
! 123 !
! 456 !
! 789 !
+----+
only obviously not all numbers would be there, only the ones that I think might not be used in column / rows
Good job, though