Variable game board grid size from three-by-three to nine-by-nine (Larger than nine-by-nine is simply ridiculous and unplayable in mobile phones)
Variable game ai difficulty (easy, medium, hard)
The Simple game is the most simple variation of Tic-tac-tao with a three-by-three grid with two players. The player who succeeds in placing three of their marks in horizontal, vertical, or diagonal is the winner.
Simple Game AI
Currently, in hard mode, AI uses a strategy rather than an AI search algorithm like MinMax. This strategy consists of these steps: Win, Block, Fork, Block Fork, Center Play, Corner Play, and Side Play.
Strategy's source: Flexible Strategy Use in Young Children's Tic-Tac-Toe by Kevin Crowley, Robert S. Siegler
In Easy difficulty, AI plays a random empty cell in the grid. In Medium difficulty, AI chooses between Easy difficulty and Hard difficulty for each move based on a 50/50 chance.