Summary: blackball. is a very simplistic, yet very challenging mind game that will strengthen your ability to think about situations very thoroughly. the launch version of the game comes with 23 levels that get harder and harder as you go along. you might breeze through the first two levels and think that this game won't be too bad, but it picks up the pace rather quickly and doesn't stop. good luck... --- if you happen to get stuck on a level and don't want to continue, the game comes with a bonus game that is fun for the whole family and does not require any kind of thinking.