there are four moves that you can do in this game: block left ............. left arrow + up arrow block right............ right arrow + up arrow block lower left.... left arrow + down arrow block lower right.. right arrow + down arrow If it looks like the ninja is swiping low and to the right, block lower right. If he is swinging low and to the left, block lower left. ETC.
I made this all by myself. I was sword fighting with yardsticks with my brother, and I thought of this game. If there is any bugs, tell me.