Concentration test game

We are going to do an experiment to test pilots ability to listen and read back instructions correctly, this while they are focusing on executing tasks that would require them to focus both functions simultaneously. We need a simple app or program with ball that is balanced on a dome and is continuously rolling away from the top. The pilot then has to use arrow keys to move the ball back to the original position. And attempt to keep it there. The sensitivity of the controls, rate of the defection of the ball needs to be adjustable to increase the complexity. A defection too far ends the session, fail! Being able to report on the accuracy of keeping the ball in place would be required.