Matsu: a logic challenge!

There are three difficulty levels that put your logical skills to the test! Do not underestimate the computer! It could be really a hard nut to crack! Rules: - Choose if you want to play alone or against the computer and select the difficulty level that inspires you the most. - When it's your turn, drag your finger horizontally to delete a number of "x". - In a move you can only delete consecutive "x" in the same line. - The winner is the player who moves last. Icons: courtesy of http://www.iconarchive.com/ (modified). Audio: courtesy of http://incompetech.com/music/royalty-free/ (modified). Both are under Creative Commons License (http://creativecommons.org/licenses/by/3.0/).