Good work so far, I have a couple of suggestions.
Currently the UI just freezes when the computer is thinking, an indicator would be a nice addition. When moving the cursor it would be even more efficient if you could just hold down the d-pad and cycle through the squares quickly.
The 3 difficulty settings are a good start, it would be even better if the player could customize the parameters involved such as search depth and time limits. Thanks for the improvements so far, I played a quick game with Spartak on Hard difficulty against Shredder at 2338 Elo and the game was a draw. A definite improvement in playing strength!